4b is / can be very expensive if not done with good fundamental reasoning and properly built ranges, having an Ace blocker is a good place to start.

However, being out of position sucks, not knowing how often BB is 3bing vs SB open sucks, not knowing how often villain folds to 4b sucks.

Therefore to make sure your not over doing things and can be comfortable 4bing for clean value and have some bluffs too you need to start off by trying to be reasonably balanced so that's its tough to be exploited.

You need to use a tool like equilab and see how many combos you would often 4b for value in this spot then try find an ~equal number of bluff combos to use, good hands I would recommend are suited A2.3.4.5 they block villains value 3b range and play well post fllop making straights, disguised trips and nut flushes. Then some other hands that either play well post flop or block villains strong 3b value hands like 89ss or KJo etc.

Picking a hand like A7s without any info oop is going to get you into lots of trouble post flop as it did in this situation.

As played I think you need to be folding turn

Everything you need to know is above! Great post!

I personally don't mind the 4bet preflop when it's blind v blind. A heap of the time his 3bet range is going to be light with plenty Ax-Kx and suited connectors who want to take down the extra 3bb in the pot. So I do think we take this down more often than not.

Flop is fine. Plenty of his 3bet range hands would try and take it down on the flop after you check.

Turn is a fold. I don't think he ever double barrels with air and you check call flop and it's not the best card for him if he doesn't have diamonds or AA. So when he leads turn he's just too strong for us to contemplate a call.

agree with @Curl-1-out. Good post!

I also agree with @Curl-1-out and I'd really like to emphasize the fact that if you want to have an active 4bet bluffing game at this limit your fundamentals should really be on point.