I think call ... KQ KJ AK KK QQ JJ QJ doesnt play it this way surely? An issue is we block nut diamonds which means draws would need to be JT / J high diamonds a lot.

Maybe he has KT.

44 would feel that smacked your 3b range and want to get it in. Combo draws want to get it in. I would really be inclined to expect some sort of JT, or more likely a T9 / T8 diamonds. As played this is bluff catching river. Turn check is fine when he checks back it should be some sort of draw he wants a free card with.

Although villain is loose he doesn't look aggressive, and a general rule about micro stakes players, even the bad ones, is that they don't tend towards bluffing any showdown value such as AJ here.

He might be getting tricky with two pair, he might have been pot controlling with a random Kx no kicker.

I always think players are morelikely to bluff the turn here if they're going to bluff at all, so I would fold.

First of all, stats doesnt mean much with that sample size.
Good sizing preflop, flop and turn standard check call.
I dont think river is a call for us, ppl dont usually bet check bet when bluffing, also ppl @ micros rarely bluff with a pot size bet on river.