IMO, .22lr with currently-available ammo, "could" handle most (possibly even 90%) of 'foraging' and hunting needs, even pre-shtf. Not legal generally, not advisable sometimes, and not 'perfect' a lot of times, but "usable". Again, for hunting and foraging, primarily; even up to our small deer. (The CCI "Velocitor" load claims 1,400 fps with a 40-grain bullet. Not a pole-ax, but that's very good for a full 40-grain .22LR round.
I know guys who won't trust anything short of a .30-06 for deer; even though we're shooting smallish whitetails, at under 100 yards. I think they're kidding themselves. Many deer have fallen to loads carrying 400 ft/lbs or less, yet we for whatever reason want "more" every season. Even I'm guilty of this kind of thinking occasionally; being concerned with having the "best" bullet in my CAR this year, when with most ANY load, it's putting out three times the power of the guns of some of the guys I hunt with. (.32-20; something like 400-450 ft/lbs at the muzzle, and he's been using it effectively with LRN or maybe LFP loads for decades. So it must be "enough"...)
Since it's not legal to use .22LR now, and I'm 'forced' to use more, it's a moot issue to me at this point.
For close-in defensive use (most defensive use is close-in), the .22lr's a poor choice compared to what else is available. Just doesn't have the power I want.
I ran "Velociter" through my Ruger Mk II Bull Barrel last year, it averaged only 1090 fps through my chrono. Very disappointing considering that sells at the same price as Stinger which gives me 1392 fps in the same gun.
you can’t even adequately define your version of SHTF. The things you do lay out, suggest that you will be the one making fatal mistakes, starting with faulty assumptions and poor equipment and tactical choices.
you should start with defining the scenario. Then present why you think your choices fit the scenario. Then, maybe people will take your suggestions seriously.