I forgot the obvious....Duh!
If you are looking for the most durable, under all conditions, handgun, the auto pistol has a huge Achilles Heel. The magazine.
It can be lost, or damaged, more easily, because it is a separate part. I know it doesn't happen alot, but it does happen. 90%+ of all autoloader problems are the magazine. And .22s are legendary for their quirks.
If you want the least possible opportunities for something to go wrong, choose a good revolver.
I've got five .22 autos, they all work pretty good. I've also got a couple of dud magazines that work, maybe. Got a couple of .22 revolvers that always work. Your call.