My thought process for whether to 3bet or flat any hand goes something like this:
a) Can I 3bet for value? If so then I pretty much always do that since I will stand a better chance of winning villains' entire stack.
If no then...
b) Can I profitably flat this hand profitably vs villains range? With the hands that OP is asking about I'm usually only flatting these hands against aggressive players opening from MP-BTN. If they open from EP then I am more likely dominated and will get into more trouble spots than I'd like to.
If not then...
c) Can I profitably 3bet bluff this hand? The answer to this will often be a yes since broadway hands like KQ, AJ etc have blockers to big hands like QQ+/AK so when you bluff with them it should work more often. Its important to note that we should be 3bet bluffing
with only the top of our folding range. How many hands we do it with really depends on the ratio of bluffs:value you can get away with. Against nits that fold a lot to 3bets that ratio will be really high while against fish you'll want your range to be pretty much all value.
Another interesting spot comes up when a TAG opens to 3bb in MP a fish cold calls in the CO and you're BTN with a hand like ATo. Our hand here is pretty borderline for flatting. Probably -EV though it depends a lot on different factors such as your skill edge over the other players. In this spot we can often squeeze with the intention of bluffing the TAG (getting him to surrender his equity in the pot) while isolating and getting value from the fish who can have a really wide range here.