Let's simplify this for you. Your main issue is that you're not using a bright white Basking Bulb but rather a CHE. This is very, very bad for a desert reptile, as your main goal is to replicate natural sunlight as closely as possible. A CHE should only be used if a nighttime heat source is required, and 99% of the time it is not require at all, as the Australian Desert is very, very cool and Pitch black at night. So as long as the temperature at nighttime is at least 65 degrees F, which it most likely is with no heat source, then you need no nighttime heat source at all.
You need 2 total lights for a Bearded Dragon, both should be right alongside each other over the Hot Side of the tank (not end-to-end, but rather right alongside each other), and whatever you are using as his Basking spot/platform should then be moved so that it is directly under these 2 lights, so that your dragon gets both while he is basking.
The first light needs to be a bright-white colored Basking Bulb in either a dome lamp or a clamp lamp (dome lamp is better), sitting on top of the mesh lid (never use ANY colored basking bulbs for a bearded dragon, they see in full color and this can confuse night and day for them and mask their food). This bright-white colored Basking Bulb needs to be the adequate and correct wattage to get the temperature zones within the correct ranges, and you shouldn't have to use any added CHE over the Hot Side of the tank to achieve these temperatures at all. At the very most, you may need to add a second bright white Basking Bulb of a much lower wattage over the Cool Side of the tank to get the Cool Side Ambient (air) Temperature between the necessary 75-80 degrees F. But you won't know whether or not you need to add a second bright-white colored basking Bulb until you get the correct UVB tube and the main, high wattage bright-white colored Basking Bulb set up over the Hot Side of the tank, right alongside each other, and let the tank heat up for at least an hour or two.
I don't know what size of tank/enclosure you have, but just for reference, typically a single 100 watt, bright-white colored Basking Bulb over the Hot Side of the tank will get both the Basking Spot Surface Temperature and the Hot Side Ambient (air) Temperature within the correct ranges. So if you have a tank that is larger than a 40 Gallon Breeder tank then I would try a 125 watt bright-white colored Basking Bulb or even a 150 watt, but keep in mind that you will most likely need a bright-white Basking Bulb that is of a lower wattage than the CHE you've been using, though your temperatures sound like they are extremely low, which is one of the main reasons, or the main reason that he is sleeping so much and is so lethargic and not eating nearly the amount of food he should be. Babies like this typically eat between 40-60 live insects every single day (smaller than the space between their eyes), so you can see how much of an issue you have going on due to using that CHE. Dragons get ALL of their heat from bright-white light from above, that's it, so that's why you're having such issues.
As far as the type of bright-white colored Basking Bulb you should buy, you can either buy a more expensive, Reptile-Specialty Basking Bulb that you would buy at a Pet Shop (IT MUST ONLY BE WHITE IN COLOR, NO RED, BLUE, YELLOW, GREEN, BLACK, PURPLE, ETC., ONLY WHITE!!!), or you can simply use a regular, household, Halogen Indoor-Flood Bulb, like the kind that you buy at a hardware or department store. They are all bright white in color, so you don't have to worry about that, just make sure that #1) It's Halogen (not LED, that's becoming all you see anymore, but in most US hardware stores like Lowes, Home Depot, Tractor Supply, etc. they still sell all wattages of Halogen Indoor Flood Bulbs), and #2) That it's a Halogen "Flood" Bulb, and not a "Spot" Bulb, because the "Spot" bulbs focus all the light on one spot, while the flood bulbs fill the Hot Side of the tank. You'll pay less for the Halogen Indoor Flood Bulbs, but the choice is yours. I'd buy a few different wattages, like a 100 watt, a 125 watt, and a 150 watt, start with the 100 watt and go from there, and then take the other ones back to the store and return them once you figure out what is the appropriate wattage for the temperatures. And just remove the CHE completely.
The second light you need is a strong UVB tube, a long tube that is at the very least 18", but I recommend at least a 22" or 24", depending on the strength you buy. You said you already have a Reptisun T5HO UVB tube, which is exactly what I have used for years and what I always recommend for a Bearded Dragon, but yes, you must order a 10.0 (means 10%
UVB light) rather than the 5.0 (only 5%
UVB light). The 5.0 UVB tubes are only 5%
UVB light, and as such must be much, much closer to your dragon to be effective. Also, they cannot be on top of the mesh lid, as the 5" UVb being blocked by 40% is basically eliminating any
UVB light from reaching your dragon at all, and this is problem #2 that you're having.
A Reptisun 10.0 T5HO
UVB light can sit on top of the mesh lid, though at this point, because your dragon has been deprived of pretty much any
UVB light at all, I would still mount the 10.0 UVB tube on the underside of the mesh lid by poking 4 holes in the mesh lid, and then using long zip ties, twine, wire, shoelaces, etc. to strap the entire fixture to the underside of the mesh lid. Be sure that you strap it to the underside of the mesh lid that is over the Hot Side of the tank, and put it off center to one side (front or back, but not against the front or back glass, just off center to the front or back) to allow room for the bright white Basking Bulb in a dome lamp fixture to sit on top of the mesh lid right alongside the UVB tube. Then position his Basking Spot/Platform directly underneath both lights, so that he'll get both while basking.
You have a Digital Probe thermometer, that's great, but you have to know how to use it correctly or the readings will no be anywhere near accurate. First of all, both the bright white Basking Bulb and the UVB tube must be turned on and be on for at least 1-2 hours BEFORE you try to take temperature readings, to allow the tank to heat the whole way up. Secondly, you absolutely must allow the Probe to sit on the spot you are measuring for at least 20-30 minutes BEFORE you read the temperature, to allow the Probe to heat the whole way up.
BASKING SPOT SURFACE TEMPERATURE (Within the Hot Side of the tank and directly underneath the center of both the bright-white colored Basking Bulb and the long UVB tube): Between 105-110 degrees F for a baby/juvenile up to about a year old; between 100-105 degrees F for an adult a year old and older (they tend to like it a bit cooler once they hit adulthood); FYI: THE HIGHEST ANY TEMPERATURE SHOULD HIT INSIDE A BEARDED DRAGON'S TANK ANYWHERE IS 110 DEGREES F, ANYTHING HIGHER THAN 110 DEGREES F CAN BE LETHAL.
HOT SIDE AMBIENT (air) TEMPERATURE (The Hot Side of the tank that surrounds the Basking Spot/Platform): Between 88-93 degrees F maximum.
COOL SIDE AMBIENT (air) TEMPERATURE (The Cool Side of the tank that is opposite the Hot Side that contains the Basking Spot/Platform): Between 75-80 degrees F maximum.
TO PROPERLY USE THE DIGITAL PROBE THERMOMETER TO MEASURE TEMPERATURES: After you set up both his lights and allow them to be on for at least 1-2 hours, the first temperature you want to measure is the Basking Spot Surface Temperature. Place the Probe of the thermometer directly on the Basking Spot/Platform, exactly in the spot that your dragon sits/lays while he's basking. You can use the suction cup that comes with the Digital Probe Thermometer to stick the Probe right on the Basking Spot if necessary. Allow the Probe to sit directly on the Basking Spot/Platform for at least 20-30 minutes, then read the temperature and write it down. Then move on to measuring the Hot Side Ambient (air) Temperature. You do this by sticking the suction cup that comes with the Digital Probe Thermometer to the glass of the tank on the Hot Side of the tank that is surrounding the Basking Spot. Make sure that the suction-cup is attached to the start of the wire, right below the Probe, and then stick the suction-cup to the glass about 2" up from the floor, either to the side or the front glass of the tank on the Hot Side (the Probe will just be hanging in the air while the suction-cup is stuck to the glass). Allow the Probe to sit there for at least 20-30 minutes, then read the temperature and write it down.
If the Basking Spot Surface Temperature and the Hot Side Ambient (air) Temperature are within at least 10 degrees or less of the ranges I listed above, in either direction, it may be possible to simply raise ONLY the Basking Bulb (if the temperatures are too high) or lower the Basking Bulb (if the temperature are too low) in order to bump these temperature up or down in order to get the Basking Spot Surface Temperature within 105-110 degrees F, and the Hot Side Ambient (air) Temperature within 88-93 degrees F. Remember though, that the Basking Spot/Platform must be within at least 11" of the Reptisun 10.0 T5HO UVB tube (THIS DOES NOT APPLY TO YOUR CURRENT 5.0 UVB TUBE, WHICH HAS TO BE WITHIN 3-4" OF HIM TO BE EFFECTIVE, WHICH YOU CANNOT DUE BECAUSE IT CAN CAUSE SEVERE EYE AND NEUROLOGICAL DAMAGE, AS WELL AS BLINDNESS; I AM WRITING THESE TEMPERATURE DIRECTIONS ASSUMING THAT YOU'VE MOUNTED A REPTISUN 10.0 T5HO TO THE UNDERSIDE OF THE MESH LID OVER THE HOT SIDE OF THE TANK, AND RIGHT ALONGSIDE A NEW BRIGHT-WHITE, HALOGEN BASKING BULB). So, while you obviously cannot move the UVb tube because it's strapped to the mesh lid, you can however move the Basking Spot/Platform or use a higher or lower Basking Spot/Platform to alter these 2 temperature ranges, if necessary, AS LONG AS THE BASKING SPOT/PLATFORM STAYS WITHIN AT LEAST 11" OF THE 10.0 T5HO UVB TUBE.
If however these 2 temperatures are over 10 degrees outside of the correct ranges in either direction, then I suggest not trying to raise or lower either the bright-white Basking Bulb or the Basking Spot/Platform, but rather just going to the next higher or lower wattage of bright-white Basking Bulb, allowing this new Basking Bulb to be on for at least 1-2 hours, and then taking these 2 temperatures again.
Once you get both the Basking Spot Surface Temperature and the Hot Side Ambient (air) Temperature within 105-110 degrees F and 88-93 degrees F, respectively, then you can move on to measuring the Cool Side Ambient (air) Temperature. You do this the same way you measured the Hot Side Ambient (air) Temperature, by attaching the suction-cup to the wire of the thermometer, right below the Probe, and then sticking it to the glass on the opposite Cool Side of the tank, either the glass on the Side or the Front of the Cool Side of the tank, and about 2" up from the floor of the tank. Allow the Probe to hang there for at least 20-30 minutes, and then read the temperature.
It's extremely important that the Cool Side Ambient (air) Temperature fall between 75-80 degrees F as a maximum, because your dragon always needs an area inside his tank to go that is considerably cooler than the opposite Hot Side of the tank, so that he can cool down whenever he wants to. In most cases, it's much easier to adjust the Cool Side Ambient (air) Temperature than it is the other 2 temperature zones, because usually once the Basking Spot Surface Temperature and the Hot Side Ambient (air) Temperatures are correct, the Cool Side Ambient (air) Temperature will fall within the correct range of 75-80 degrees, or it will be a bit cooler, but it's very rare that it's hotter than the proper range. If it measure no higher than 83 degrees, then you're okay and can leave it alone, and if it measure no cooler than 70 degrees you're alright and you can leave it alone, as the Cool Side Ambient (air) Temperature does have a little bit of play in it. However, it's extremely important that the Cool Side Ambient (air) Temperature not be any higher than 83 degrees F at an absolute max. This usually doesn't happen, but if it does, I suggest trying to just raise the bright-white Basking Bulb up an inch or two, waiting 1-2 hours, then measuring the Cool Side Ambient Temperature again, this will usually correct that problem, if it occurs.
More often than not, if the Cool Side Ambient (air) Temperature does not fall between 75-80 degrees, it is going to fall lower. If this temperature ends up being lower than 70 degrees, you'll need to add a second bright-white Basking Bulb over the Cool Side of the tank, either in another Dome Lamp Fixture that will sit on top of the mesh lid over the Cool Side of the tank, or in a Clamp Lamp Fixture that will clamp to the edge of the lid and be pointed over the Cool Side of the tank. Keep in mind that you're not going to need a very high wattage Basking Bulb over the Cool Side, no where near the wattage of your main Basking Bulb. For example, let's say your Cool Side Ambient (air) Temperature ends up measuring at 60 degrees, your best bet is to start off with a 25 watt bright-white Basking Bulb added over the Cool Side of the tank, allow it to be on over the Cool Side for at least 1-2 hours, then again remeasure the Cool Side Ambient (air) Temperature, and see if it falls over 70 degrees but lower than 83 degrees. If it does, you're done (and most likely it will). It's all relative to how many degrees you need to raise the temperature, but a good rule of thumb is "Always start with the lowest available wattage and go up", and "Always get a lower wattage, bright-white colored Basking Bulb than you think you'll need". We always tend to think we need more wattage than we do.
Again, please completely remove that CHE, it's not the way that a Bearded Dragon, being a Desert Reptile that comes naturally from bright, intense, natural sunlight all day long, needs or wants to get his heat, and this is what is causing all of his lethargy and your extremely low temperatures. Bright white colored light and strong, intense
UVb light is what he needs.
Be sure to replace your 10.0 T5HO UVB tube once every 10 months to a year at most, as that is when all of the
UVB light will have decayed. And please be sure to leave both his bright-white colored basking bulb and his UVB tube on every single day for at least a 13-14 hour photoperiod.
Also, never feed your dragon in the morning before both of his lights have been on for at least 1-2 hours, and never feed him at night without allowing both his lights to remain on after he eats for at least 1-2 hours. This will allow his body to remain at the proper temperatures to digest the food that he eats, and to absorb enough adequate
UVb light to absorb and process (use) the nutrition from the food that he digest.
