I recently took my 3DS out of storage, after it hadn’t worked for a couple of years. It turned on, so then I went and tried putting in a few SD cards I had lying around. After about 5-10 minutes of this, it started to only work if you took the battery out for a few seconds, and then an hour or so later, it wouldn’t turn on at all. I’ve put the battery in a 2DS I have and it turned on so I know the battery’s good but other than that I’m at a lose of what to do.
Also the circle pad was replaced about 6 months back and the right shoulder button hasn’t worked in years (just including incase it helps). I would also ideally like to keep all the data on the system if possible, this was my childhood 3DS so I don’t really wanna lose my system saves and Eshop purchases.