I've been using a push on PV pump since 1967. The secret to not damaging the valve is to make sure that the pumping force isn't put against the valve. I use two techniques for this.

One is to arrange the bike so the wheel has some room to move back and forth as the pump moves. If the wheel is braced and has no room to sway, all that force is in the valve.

The second is in the secret pump handshake, or left hand grip. Hold your hand ad if hitchhiking, with the pump held in your fingers, and your thumb braced against the rim or tire. This way the pump is braced directly to the wheel (via your hand) and you won't be pushing on the valve. This takes a tiny bit of practice, but once you get used to the grip it becomes second nature.

When finished pumping, release the thumb lock (if you have one) and instead of wiggling the pump to work it off, hold it straight and give it a karate chop near the valve to knock it clean off.