Same here. a few rounds of .357’s wore my wrist right out. I’m figuring (praying) that if I should have to use them for self-defense, the adrenalin will get me through it. But for target practice, 38’s all the way.
My Ruger .22 slides a little nicer than the 9mm. However, it’s one you grip from the back, typically with only your first finger and thumb. So you still need a decent grip. Any exercises your wife can do to strengthen her hands?
My wife is not really interested in shooting, or even practicing much so it is probably a moot point. She does not like the noise, even with double hearing protection. I taught her gun safety and marksmanship using a Thompson Contender with .22 barrel using the Aguilla Collibri ammo that is just primer and makes almost no noise.
I got her the Key Defender pepper spray to carry around. She thinks I should be there if something bad is going to happen. I just tell her that if she can tell me when a bad thing will happen then she should not be there.