RB doesn't work at all

I’ve come across this with other devices that utilize essentially the same sort of module. They are a pain to take apart and re-assemble. However in each case what I found was barely dirty/dusty/oxidized/corroded internals.

My new nintendo 3ds power button was randomly turning on and or off. I disassembled it and used canned air to blow around the little button into the button module itself (not the external button). You might need some way to depress the button or shove it a little to the side, so the blast of air can fully enter the module. In another case I had canned air didn’t work but contact cleaner did.

But since you plan the nuclear option, full replace. Wouldn’t hurt to try air or contact cleaner first.