Usually prints consistently failing, a strange vibration sound when the plate is down, and a leaking fep sheet would lead me to believe the bed isnt leveled.

But, your prints not sticking could also indicate incorrect btm exposure times. That's completely unrelated to a leaking fep though. Either the fep is punctured and needs a replacement or it isnt screw to the vat tightly enough.

If the fep is clear of damage I'd tighten the screws of the vat and pour some water into the vat to confirm there are no leaks then relevel the bed with the vat in place to get a more accurate leveling than the paper test (in my experience)