I use this kind of self adhesive bumpers:

I've never had one fall off in 5+ years, and I use/ wash my end grain cutting board almost daily. I've given away dozens and nobody has ever reported a bumper becoming unglued. I know, multiple anecdotes don't make reliable data, but don't believe everything you read on the Internet.
After applying the oil/ wax finish, I take a paper towel, dab a little mineral spirits on the area where the bumper needs to go, and remove any finish that's on the surface. Dry with the other side of the paper towel and stick on the bumper.
The main reason I stay away from screw-in feet is because you're screwing into end grain. Eventually, those will come out. Epoxying on feet will certainly work, but it also means they can never be removed without damaging the board. My guess is that the wood will last longer than the rubber, so it would be nice if they could be replaced at some point.