My plan was obv to stack off against the fish but that didnt work out.

What are you doing against the big 4-bet?

If I would be the CO I would flat all my strong hands, which I would want to play, to keep the fish in the pot.

I think in a vaccum its a good spot to 4-bet as a bluff because even though my range is depolarized and strong I have a hard time continuing to the CO's 4-bet.

I think I am 3-betting a range like this: 10.56% 99+, AQs+, ATo+, KTo+, QJo

Beeing slightly deep I have trouble continuing everything except QQ+, (AK). Even Jacks are not fun to play because I dont want to risk 135bb preflop with JJ.

But on the other hand there is imo more value in flatting QQ+ for the CO because the fish will overcall most of the time with a very wide range.

Also the 4-bet sizing is very big which looks to me kind of like he wants the FEQ.

Due to his sizing calling is imo not a viable option, so either push or fold.

How do you continue in this spot?