Canon T7 issues with SD cards
Camera is a EOS Rebel T7. At first I had issues getting the camera to turn on, but that was eventually fixed with a new battery and fiddling with the battery compartment switch. It'll now turn on, but as soon as an SD card is inserted it will not turn on. I've tried an old previously working card, that same old card but freshly reformatted via PC, a new 32gb card unformatted, the same new card formatted via PC again, and a new better brand 64gb card (unformatted and formatted just like the previous cards). I've tried the reset using "P" mode, letting it sit overnight, etc. I've tried both my 75-300 EF lens and an EFS 18-55 lens. Is there another switch that could be damaged or seized for the SD card? Any recommendations on cleaning the SD card slot? I've tried everything I can think of short of cleaning, because I'm not quite sure what will or won't damage the SD card contacts. At a loss here.
I should add that this camera was purchased from a pawn shop, but previously working for the 6+ months I had it. It sat for maybe 1-2 months unused before these issues began.