iPhone 7 stuck on apple logo, computer can read files?

I work for a phone repair company, i have tried everything. New screens, unplugging the camera, updating, restoring, letting it sit for an hour or two. It will load through the apple logo sporadically, so i have a backup of the phone, but it always goes back to the apple logo. Wether it be on startup or just randomly while the device is on.

The weirdest part is that the computer is able to access files on the device, even though its stuck on the apple logo. I've tried restoring from back up twice. i'm not sure what else to do? I can't give up because the phone comes on every once in a while, there has to be something i can do to make it stay on. Please help! any ideas are welcome!