Dubia are way too big... Your looking for 1/4 no larger. Crickets look to large as well. Dubiaroaches.com sells the size you need. This link will give you a discount on your first order:
http://i.refs.cc/NpiKgOoq?smile_ref...hbSIsInNtaWxlX2N1c3RvbWVyX2lkIjoyODg5NTcyMDN9
You need to go today to find a big ficus or umbrella tree for that cage. It should fill out all the way up to those top ledges. Baby has to have this for security. You have dragon ledges and you are not using them the way they should be used...
You need a feeder run... This can be home made or purchased... He is not going to go down to the bottom and eat out of that cup. He is exposed and scared.
Here are tutorials on the ledges and how you should have the enclosure set up...
https://dragonstrand.com/getting-the-most-from-your-dragon-strand-dragon-ledges/
https://chameleonacademy.com/case-study-2-x-2-x-4-cage/
Feeder run tutorial or links to buy.
https://dragonstrand.com/constructing-a-chameleon-feeder-run/
This one in the large size
https://tkchameleons.com/collections/accessories/products/shooting-gallery
Or this one in the three inch size
https://www.fullthrottlefeeders.com/
Right now because that is the set up and feeder size I am leaning towards extreme stress and improper feeder size being the reason this baby is not eating. You have to make changes... Like today. Without them this cham will die. He is too young to not be eating.