Not sure why you would be getting the crash like that but try removing the return; you have in the loop code as you don't really have anywhere to return to.
I don't have a RFID card and I'm at work so no access to an ESP32 to test with.
Is the RC522 library you have installed the latest version (currently 1.4.0) and do you have a pinout (see below example) of the Lolin32 OLED board your using just in case the problem is with the pin numbers.
Try the example here to see if it works.
