So i just bought an ender 3 off 2nd hand market (he seemed legit he sells a LOT of 3d printers.) after 2 days if leveling it worked decent now after s couple good prints i’m having leveling issues again and im starting to think it is not a leveling issue. i do the paper trick and cleaned my bed after every use and it’s all the sudden out of level, haven’t accidentally hit the knobs etc.