You can download an stl for the battery cover. I modified it to allow the backpack controller to attach to/detach from the main controller. The original is in a box somewhere safe and well.

Then there’s the back paddles. Only two of them.

Speak for yourself. Mine has 14 lol

A bit of unsolicited advice now you’re in to tinkering. Set up some kind of NAS.

Having everything available wherever and whenever you need it is so much better than messing about with thumb drives.