They are still folding the blinds fairly often, so I would continue to open a wide range on the button. However, I would drop the worst hands from my range. I would widen my 4bet value range a lot and increase my 4bet sizing to deter them from just flatting 4bets.
What are your thoughts on just 4bet shoving 100bbs to avoid making a mistake postflop and guaranteeing ourselves a showdown? I think that would be okay with hands like AQ and 99.

Are they 5bet shoving or 5betting small? If they are 5betting small enough, we could add a 6bet bluffing range.

Because they are 3betting and going crazy postflop, I would just flat their 3bets with my premium hands to trap.