No, they cannot. Sometimes they can even wipe the storage using the recovery boot menu, but as soon as the device contacts apple when connected to a network it’s going to prompt for iCloud credentials and not allow any further use without them.

You clearly have zero experience in this area, this is and has been a very well known issue with iPads entering the waste stream for a very long time, and everyone involved knew it was coming to computers as well when Apple announced the T2 chip and how it was going to be integrated with activation lock.