Bearded dragon staying in hide and more!

Hi my almost 2yr old bearded dragon Reptar has been acting really weird lately so I'll start with his set up, I recently moved him out of a 75g tank to a 40 gallon breeder thinking it was heating or uvb issues (not getting high enough to reach lights) but 100w heat bulb and 12% arcadia desert tube, humidity stays in the 30 to 40 range dusting live feeders 4x week and salads 2x a week he is currently not eating! Also been trying liquid calcium, his diet is collard greens, mustard greens, turnip green, bell peppers and fruit occasionally, feeders are dubia, crickets, superworms. O and temps range from hot spot 103 to 80 cool side so here is the issues! First a few weeks ago i noticed his front legs beginning to shake and back legs not working so i thought mbd or impaction but i put him in a soak and he pooped fine started liquid calcium for a boost and he seemed to be fine bout a week later it happened again so i took him to my vet (not a herp vet) and he said he looked fine weight is fine and he was walking fine when i took him it's weird that it comes and goes but he told me he didn't know what was wrong with him and told me take him to a herp vet but i do not live near any and trying to figure out what to do in the mean time but anyways he also said he looks really weak he does to me too ! But he is now not wanting to bask or eat if i leave his hide in he will stay in there all day and sleep so i been trying to take him out to bask but he will get under his bridge and lay there instead. He is walking fine when i try to get him to move around but he doesn't stay moving for long he hasnt ate or pooped in about a week just wants to sleep he done that a few months ago and i took it as burmation cause when he finally did come out he was fine basking eating ect. Im not sure whats going on any advice is greatly appreciated any questions please ask thanks.

Ok so the Arcadia UVB is where on the tank? This is imperative for proper rays ---- if you have it in the tank it needs to be 12-15 inches from basking decor - if its on top of the screen it needs to be 8-10 inches from basking decor - I was going to say to move him back to the 75 but since he is sick leave him in the 40 -- and I would set the 40 up like a hospital tank - if hes weak and not moving I would get your basking light and UVB over the top of that tank set him in the middle and take the screen off so hes got the full rays of the UVB -- it should be 12-15 inches from him w/ no screen --- have your basking spot around 100 but it needs to be taken w/ a digital probe thermometer NO stick ons --- He needs to stay hydrated and I would start slurrys - blend up some greens w/ some water for hydration - add your liquid calcium and start feeding him slow and amounts of 1 ML at a time couple times per day - feed slow so he does not aspirate -- go in from the side of the mouth and let him swallow what you put in before adding more -- I was gonna ask how old is the Arcadia?
Karrie