Okay, well first of all congrats on the new beardie...
There can be a "Relocation Stress" period where they refuse to eat that can last for a week or so, that may be playing a part in it, but how is his health overall? Size? Can you post a photo of him?
Did you get the Reptisun 10.0 T8 UVB tube from the prior owner? If so, do you know how old it is? And do you have it strapped to the underside of the mesh lid and within at least 6" of his Basking Spot/Platform?
How big is his tank/enclosure? I'm asking these questions because #1) The T8 UVB tube is the weaker of the 2 strengths, the T5 tubes are much stronger, and you absolutely must have all T8 UVB tubes mounted UNDERNEATH the mesh lid, they are too weak to be blocked by the mesh lid; you have to use either zip ties, wire, twine, etc. to strap the entire tube fixture (hopefully it has a reflector inside it as well) to the underside of the mesh lid, over the Hot Side of the tank, right alongside the bright-white Basking Bulb, so that both lights are sharing the top of the Hot Side of the tank. Then his Basking Spot/Platform needs to be directly underneath both lights so that he gets both while basking, ans so that his Basking Spot Surface Temperature is between 105-110 degrees F.
In addition, all T8 UVB tubes must be within at least 6" of the Basking Spot/Platform, and THEY MUST BE REPLACED ONCE EVERY 6 MONTHS MAXIMUM, AS THEY STOP EMITTING ANY
UVB LIGHT AT THAT AGE...So if you don't have that T8 UVB tube underneath the mesh lid, within 6" of his Basking spot, or it's older than 6 months old, and if you're not leaving both lights on for at least 13-14 hours every single day, he will lose his appetite, become lethargic, and eventually develop MBD.
\I asked what size his tank is because 200 watts of heat is a lot. Usually a 40 gallon Breeder tank requires a single 100 watt bright-white colored Basking Bulb over the Hot Side of the tank in order to achieve a Basking Spot Surface Temperature between 105-110, a Hot Side Air/Ambient Temperature (surrounding the Basking Spot/Platform) between 88-93 degrees F, and then a Cool Side Air/Ambient Temperature between 75-80 degrees F and NO HOTTER. THIS IS EXTREMELY IMPORTANT.
And he needs absolutely NO NIGHTTIME HEAT SOURCE AT ALL as long as his tank is at least 65 degrees at night, which it most likely is, as your house would have to be at 60 degrees or colder at night for his tank to drop below 65. Dragons come from the Australian Desert, which is not only Pitch-Black at nighttime, but also very cool, even cold at nighttime, and if you have the Air/Ambient Temperature of his tank higher than 65-73 degrees at night then he's not sleeping well, his body is not resting/recovering, and this will cause great stress and a lack of appetite, as well as other issues. A lot of people who already have a nighttime tank temp of 65 degrees or hotter then just automatically add a CHE and they end up causing a lot of issues. My suggestion is to totally eliminate the CHE at night and let him sleep comfortably, he doesn't need it and it can be very detrimental to his health, especially if it's any higher wattage than like a 10 watt CHE, as even if his tank was down to 55 degrees at night, which it's not because your house would have to be 50 degrees for that to happen and you'd be freezing yourself, you'd still only need a 10-20 watt CHE to get his tank temp up over 70 degrees. So any higher a wattage is going to put his nighttime tank temp over 80 degrees, which is causing him stress.