Hi there,
Welcome to the site!
Great question, and I'm glad you came and asked. Temperatures are the most important thing to a dragons health, so making sure you're doing it right is the most important thing you can do
Ambient temp is fine for cool side and warm side readings. However, the most important temperature is the basking SURFACE temperature. This is the spot where your dragon actually will go to bask. And this needs to be the surface temp.
Those dial stick on thermometers, sorry to say, are junk. They don't even read the ambient air temps very accurately. I've tested some and found them to be off by over 20 degrees. In one extreme case, it was off by over 40 degrees. So needless to say, they are not to be trusted with such an important task as this.
You will want to get a digital thermometer with probe end. Luckily they are super cheap. You can pick them up online for around 5 bucks, and usually less than 10 at your local petstores.
You just simply place the probe on your basking site, and let it come up to temperature. Just make sure the probe is actually resting on the site. This will give you an accurate surface temp. At least within a degree or two. Unlike your dial thermometers which have no way to give you a surface temp.
I have a feeling based off of what you described that your tank might be too hot. However that's just a guess, and until you get a device to test your temperatures accurately, we are all guessing
So to be clear, do you have a total of 4 bulbs? 2 powersuns, a zoomed, and a reptisun? you said an 80 and 100 watt powersun. If so that is way overkill.
Ideally, most of us here like using a long fluorescent UV bulb, and 1 basking bulb. The basking bulb provides the proper temps, and the long fluorescent UV provides the uv for the tank. Those screw in UV bulbs (which is what I assume you have on your cool side) don't really put out proper amounts of UV for bearded dragons. However, the powersuns do, but only if they are at the proper distance.
If you could clarify your lighting setup a bit we could help more. Or post a picture
But definitely get a digital thermometer with probe end and find out what your basking surface temp is. After that you can place the probe somewhere on the cool side to read the cool sides temp.
-Brandon