After disassembling one of those analog sticks that is sticking (staying in the top position), I’ve noticed that the bottom part of the plastic stick that touches the bottom plate has been damaged due to friction at the joint, and it appears to have worn out some plastic there. Probably the easiest fix is to replace the whole analog stick part, the other more involved way would be to use some epoxy or cover the area with a thin layer of plastic. 3D printing the piece might be an option, but I’m not sure how long that might last, and it needs more precision than the cheap 3d printers can provide these days..