Why do my headphones keep turning on?

A few months ago, my headphones started to turn itself on when it was in the off position. As a quick fix, I'd set it to the on position, then turn it back off. This would work for a few minutes before turning itself on again. I wasn't having it, so I just let the battery drain and not use it.

I tried to use it again lately, but the problem later evolved to my headphones being unable to pair to new devices when the power switch was set to the Bluetooth connection position. (They were connected to my phone and laptop, but I disconnected it after it stopped working.) I looked around and the issue could be from a faulty power switch, but a) I don't know if it really is from it (my headphones are from 2018) and b) I don't know how feasible it would be for me to repair them myself or get someone else to do it.

The QC35IIs have seen me at my highest and lowest, and I'm saving my money for my college tuition right now. I'd hope that these would make it to at least 2027, but things aren't looking good if I can't get this issue resolved.