I agree with these responses:
22.5 big blinds would be considered short stacked, but not short enough where you have to shove most playable hands. In the situation you described I think a raise is appropriate. KK is good enough where you can try to induce players to call or reraise you. With a middle pair a shove would be more appropriate.
I'd raise but not an all in. Especially with an under the gun limper. There is a chance he shoves when it comes back to him and I'll always take my chances with KK.
They highlight how KK is strong enough that you really don't mind whatever happens if we just raise small, but with some other hand types we sort of prefer to just take it down (or force the all in right here and right now).
From a philosophical standpoint, the whole concept of "short stacked" is a little outdated imo and I think you're trying to also ask the point at which it becomes necessary to choose shove or fold as your only two options. There will probably always be a stack depth where it's mathematically correct to pick one of those two (and not raise smaller), but over time, poker theory has pushed this number first larger and then smaller.
If you look back ~15 years ago, it would be considered crazy to go all in on a 10bb stack with a weak hand because you still have room to play, and you'd probably be doing some limping too. Then 5 years ago it'd be considered sort of weird to do anything other than jam or fold a ~15bb stack. Today, the number has sort of shifted downward. You can find some pretty competent opponents minraising off of 10 and 11bb stacks, and even folding to jams sometimes.
So there's definitely grey area here, but particularly in soft fields, you won't go too wrong playing straight up, and just trying to maximize value with your really good hands, and maximizing fold
equity with the rest when you get down to that ~20bb zone.