I've only had one beardie, a rescue that was near-death from being fed only crickets (the large back legs tend to block up beardies...beardies have a big mouth
& look like they can easily handle larger crickets than what they should be given) and from ALSO eating some of the wood shavings (in presumed desperation)
that he was kept on...needless to say, he was "beyond constipated" & starving to death. Anyway, when I got him cleaned out (oral doses daily of mineral oil &
warm water soaks) he was EAGER to try different colorful foods. But, he soon had his favorites so it's rather like getting a little kid to eat their dinner & not
desert first (& then they're too full to eat the healthy stuff...). In the morning I only fed the veggies & fruits...only later in the day did he get some worms etc.
I found that if I mixed the worms into his 'salad' he'd carefully pick them out.

There is a HUGE list of good veggies & fruits that beardies enjoy...as well as a list of things NOT to offer. But I think you have to learn not to "cave in" to his
demands...they're just like kids, lol. Are you chopping up the fruit/veggies enough for him to eat & not choke on? What have you tried feeding?

Another thing: try taking him outside (temps. permitting) for some REAL (& well-supervised) sunshine. If you got him in March, then his UVB light is getting "old"-
unless something has changed since I used them, they need to be replaced about every 6 mos. (even if they still light up, use them elsewhere just for light) as
they lose their effectiveness at that point. Also, how far above his basking spot is his light? Too far from the dragon & it's ineffective.

A dose of REAL sun generally perks up lizards such as dragons as far as their appetite goes...& maybe when he's hungrier, he'll be more willing to eat whatever's
on his plate instead of playing hard-to-feed?

Maybe your vet can turn up other answers (-I hope?) but that's about all I can suggest from what you've said.