Should I have cbet here, also sizing

hi rpm,

I moved down yesterday.

Yes, I butchered it. I 3bet his opening raise because I thought I'd take it down right there a lot of the time, or take it down at the flop.

My plan if he called was to cbet the flop if he checked it to me and the flop texture was favourable.

If he 4bet, I didn't really have a plan, other than that I'd obviously fold to a shove or bigger 4bet. Not having a plan here was one reason why this hand went so badly.

When he did 4bet, I called because he obviously had a hand he was likely to be willing to get it in at the flop with, and he was giving me odds to setmine. I figured that, plus FE at the flop, made the 4bet an OK call, but the issue as you've identified is that I should never have been having to make that decision in the first place.

Once he checked the flop to me I figured after 3betting him then calling his 4bet pre he put me on {AK/KK/QQ}. If the flop had brought a single ace rather than 2 I think he might have laid down KK to this bet. In fact, even with the 2 aces on board, he did think for a long time then just flatted the cbet, so I'm pretty sure he had KK or QQ.

None of this excuses a poor cbet in a spot I should never have got into in the first place, I just say it all so you can see my thinking process and hopefully help me see where it's wrong and how I can improve it.