As a lefty, I have had to adjust to more than just a right handed dominant plethora of firearms. (Amongst other things),...However, those things have to be overcome.
If there are issues, it's not with the firearm. Especially a Sig Pistol. They don't make firearms for a southpaw market,...like others,....
A good shooter, who finds a firearm that works whether a PPK/S,, or otherwise a "righty" firearm, has to simply adapt to the ergonomics of the pistol.
Hence, the Natural Superiority Of The Left Hander,....We overcome and adapt.

Change of grip? Not every grip will work on every pistol, especially a lefty.....