I have difficulty defining a somewhat viable 3bet calling range OOP.

Say we open to 3X from the HJ, the loose BN 3bets to 9X, blinds fold.

Say we 4bet something like 13-15% of our opening range for value + an adequate 4bet bluffing range which might give us a 4bet range somewhat short of 30% of our opening range.

I think almost all players have a calling range in this spot. However, I find it extremely hard to achieve good flop coverage when designing a calling range. Intuitively, I would be inclined to call hands like ATs-AJs, KQ, KJs, QJs, 55-99 (depending on whether I 4bet 99) which completely misses most low card flops (< Txx) so that I end up with bare overcards 70% of the time.

I could of course call A2s-A9s but this doesn't add too many TP combinations, and I don't feel I could play all of these profitably. I could also call 76s-JTs which would give me an OK flop coverage I think, but I am unsure I can call 76s profitably. Maybe I am wrong there and 76s is a super standard call nowadays (I am just getting back into the game after succesfully playing midstakes a few years ago).

What do you think? What could a typical midstakes player's calling range be composed of in this spot?