say the player pool folds to much to 3bets whats the best the exploit?
1 3bet hands that arent normally in our 3bet range at all
2 turn hands that are pure calls to pure 3bets
3 turn hands that are a mix between calling and 3betting to pure 3bets
4 turn hands that are a mix of folds and 3bets to pure 3bets
5 some strat i havent though of

also to be clear talking about preflop

by best expoit i dont necessary mean the one that attacks the over folder the hardest but the one that gains us some level of EV while being the most difficult for Villain to re-exploit

If people are overfolding then their calling/4bet ranges will be stronger than normal. How do we account for this? Well, some 3betting hands like QJs, KJs, etc can become calls because they don't do great when called and are often dominated. We can choose to replace them with bottom of range calling hands as bluffs. When they get called, you are probably doing pretty bad, but you are almost definitely undominated so you will still be pretty live! I'd rather have 65 v AA than AK v AA, for instance.

How much you move to your calling range depends on the level the deviation (like, do they call QQ,KK,AQ, and 4bet AK,AA, or are they looser than that?). If they are super overfolding then you could even think about moving some hands like KQ, AQ that are essentially always drawing thin down to your calling range and turn those into bluffs (like 65s, etc).

Now in practice they almost definitely have a looser range than the above I stated...that was only to demonstrate. BUT I think the same principle should apply. If folks are overfolding enough then you should be able to take some undominated hands like 65s, 87s, and mix them in as 3bets. This will leave you with a nice polar 3betting range of premium hands (QQ+, AQ+, etc) and some bluffs.

The key is to figure out how much they are overfolding. Are they defending at the MDF? If not, I'd say you can just blast away with garbage because you autoprofit from them folding. If they are just slightly overfolding then you might not want to adjust your strategy too much.

Taking mixed actions as pure is the hardest to counter-exploit because it's hard to notice.