Ok, first good luck finding .357 Sig. Get the .40S&W conversion barrel for a backup.
Not sure if you can say about recoil. Its going to be relative/subjective to the shooter.
I mean I have no problem w larger rounds like .40S&W (I haven't put my .357 barrel in because I can't find ammo) , but my wife would.
A bit more recoil than my 226 Navy, even after the recoil reducer.
The second thing is that we don't know the shooter. I mean... the full frame Sigs feel natural in my paws. A bit large for my wife.
So he should find what's comfortable to shoot.
The third thing... we don't know where he lives.
In the city (Chicago) I have to worry about over penetration and putting my neighbors at risk. Sure Ammo plays a part in this.
Also while I like the MPX platform.... in IL we've got this brain dead thing called PICA.

🤬
So if OP lives in IL, WA, etc ... some options aren't available. But since this is a pistol... we're mostly ok.
The fourth... remember I mentioned my wife.
Not sure if the OP is single, married or whatever. (I'm not judging.)
Any home defense gun should also be good for the wife/significant other to be able to use.
(My wife would probably grab the .22lr because of the OEG sight I have mounted on it for her... )
The other thing are sights. combat sights, or a fancy red dot sight?
And of course do you want a DA/SA or SAO w safety?
I prefer the DA/SA.
But yeah, I love my Sigs.