What I would do...
three weeks and with his background of NOT being bonded is very early to expect so much from many gliders. I would back off, slow it down. it's going to take some time...
stop handling him if he is so scared he is biting you all the time. Get him in a bonding pouch, then carry him with you around house without touching him so much for a few hours a day. give him lots of time to get used to your scent and used to the idea you might not be a predator.
Wash your hands very well with a low scented soap so he isn't trying to eat that he smells on your hand.
If you have a room to play with him in, give him some things to explore and just let him go, he doesn't even need to get on you.
talk to him in the cage, then maybe feed him treats threw the cage so he can't bite you.
It took our mary a long time to figure out what was treat and what was finger.
bonding has taken us 8 weeks to maybe 4 months with some gliders.
I think having a second glider would slow him down make him less hyper but he also needs time to get used to his new home.