1) Tighten up your range/open up your "3betting range". We could run a pure 4bet/shove line, doing some calculations in pokerstove giving us some EV numbers vs his 100% range/what we think he might call with/how much he 3bets to preflop and so on. I the middle of a game tho, this might be hard.

So, I would tighten up more oop (playing hands that do well in HU/Allin situations) and play more of a 4bet/shove game. And in position I would play abit more hands (compared to my new oop range) in a more passive ABC way.

I would also play some total rags like 72o and fold to his 3bet, but if we assume he isnt going to change his game anyway this is ofc bad.

I think we need some more info to give any specific hand ranges. Like shove calling range/postflop play/how much he makes his 3bet.

And we are assuming that no one else is entering these pots.

I'll come back for 2, 3, 4. But I'm going to add a general rule for all tricky cash game spots you end up in, if you cant beat it leave the freaking table or atleast get in a better position to do some damage.

As a example, I was playing a normal 6 max 400NL game when a laggy player to my left started to play alot of pots vs me. Being very tricky postflop. I had a hard time dealing with it and at the same time a reg tag to his left where doing realy well. I was getting ready to leave when a seat opened up to the tags left so I changed to that. I was now in a great spot and was able to win a few solid pots before the laggy player quit.