Helo guys

I'm analyzing my hands this year, and my winrate in EP and MP, does not seem very good, I have some simple doubts regarding the best pre-flop strategy for those positions, and I hope you can help me...

Let's go to the scenarios

1) Hero open 2.5x on EP, 18%, table only w regs, villain in CO w 8% 3bet x EP and no cold call range, 3bet to 7.5bb, what is the best defense in this case?

I currently fold 60%, and 4bet to 22bb 15% (KK+, AKs, A5s-A4s, AQo) KK and AKs to stack off, and A5/A4 and AQo to fold to a 5bet
And call 25% (QQ-99, AQs-AJs, KJs+, QJs, JTs, AKo)

my doubts

1) this strategy is correct or I'm folding a lot?

2)The hands picked for range of 4bet and call is ok?

3) in case the villain 3bet to 9bbs what adaptation should I make?

4)in the case of villain 3bet a polarized range with the same 8%, but in that case it would have 6/8% cold call, what adaptation should I make?

These are my first doubts, I will wait for some answers and then I will return with the others,

Grateful