I did end up selling the G22. Liked it but don't miss it.
As such this would be my current answer to the OP. Since it isn't limited to just one firearm...
This thread can be about the 'one gun' you thing every prepper should have, or which three guns they should have or simply about the ones you have. Is there one platform that covers all your needs?
My thoughts are the
Glock 45. Several reasons go into this decision. First, the popularity of Glock helps with finding necessary parts and mags which are common. It's in a caliber that is also popular and therefore easier to find 'in the wild'. The platform is a proven combat/war zone design that is reliable even when dirty, durable with high round counts likely, less parts and less lubrication necessary than many other pistols. It is also very concealable so the ability to go 'grey man' is increased while still having a defensive tool that is capable of high capacity. It is also compatible with my
Sub 2K PCC as they use the same mags. This combo can easily fit into my PCC/pistol go-bag to maintain grey man yet provide access to two capable platforms.
For carry I'd choose my
HK USPc. I'd have it in the 40S&W format with the 9mm slide/mags and 357sig barrel in the go-bag. This gives me access to a platform that can take advantage of two additional calibers should I come across them. Better to have options than be limited to a single caliber. It is a rugged design that is also a proven combat/war zone pistol. Also very concealable so grey man is still an option.
Holsters for both can be kept in the go-bag as well as other necessary gear.