I think I'd be looking to c/r this flop, our relative position is great for such a move because CO will cbet and the fish call pretty damn often, maximising our value.
I'm not thrilled getting it in on this flop though. When he stands his ground, he unlikely to have AK AQ. But we beat his overpairs. I'd give him 99-AA KJ. I'm not sure we're holding up well against this range, his overpairs have plenty of outs too.
I think c/r/f flop, or as played fold to his 4b.