no need to worry about pre flop equity, youre not getting it in pre.
you are trying to defend your opens vs someone who is 3betting you IP too much.
it is unlikely your villain would waste hands he can proffitably call with like QJs or 99, he is more likely to use Ax or Kxs maybe some low connector he felt he couldnt proffitably call, obviously he'll still have a bunch of value hands he's 3 betting depending on how wide he thinks youre calling.
if we're calling 3 bets w trash like A7s to take it away later we'll be using our reads on villain to decide how that is possible. (its fucking difficult OOP, maybe consider fucking off the table)
hope I explained that well enough ive been drinking (degens gonna degen )