are 4bet bluffs just torching cash

In my experince, in live small stake, 3bets tends to be on the larger size and very linear, there are occasional bluffs with suited Ace rags, but mostly 99+, big Ace, and KQ for value. And when they 3bet they are not folding to a 4bet.

With this setup, it is an error to 4bet bluff, and will 4bet purely for value. But what is the value threshold against that particular 3betting range? What hands can we flat? Can we just fold AK here, since calling a big bet just to fold 70% of the time does not seem profitable. Can we set mine? Is calling JJ and playing bluff catcher the right play?

Since 3bets dont happen all that often can we just fold everything and continue with KK+, especially after opening small?