First of all I would play always full stack.

I don't really know the ranges of FR but as played I would never have a leading range OTF.
Check/call seems better, then it's just a cooler.
Check/call until the end

Think Nick has it exactly. Not sure about the 0.01/0.02 NL online but I wouldn't criticise someone for folding pre (either no open or to 3 bet) UTG. I think AJs is absolute bottom of range UTG. I used to play full ring live but am mainly a 6 max player online. But once you get to the flop definite cooler.

I think in these spots you have to appreciate how good your opponent played the hand. Even starting from the 18c 3bet (I standard 20c, but guess what, you'd probably run away to full 20c, so the sizing was just right). The turn J and A river is basically you running bad (non all-in EV, but situational), it's just cards that make you feel strong and while you're actually dead. I think you played just fine, I'm 9.6bb/100 EV on $2nl as of last 50k sample hands myself, for me the keys is basically not tilting (I still do, but I try to limit that) and... well for me the big income is bluffing weak regs (read: ~85% of them) effectively and getting away in most cases when they fight back and just stacking the occasional fish here and there. I don't really see much regs with higher winrate as me as far as I'm aware for FR NL2 zoom. I think if you really want like 12 to 15*, you gotta be very sick and maybe even get away from your hand in that situation depending on your opponents tendencies and range. If his range for 3bet is like very tight you can probably check-fold flop and basically play AJ for the royal str8 and flush mostly and not rely on hit cards too much if you know your opponent to the bone and his tightness.

*if you already get more than that long-term let me book your coaching.

Why are you leading flop ?

don't donk flop

Postlfop, you do the exact opposite of what you should have done. X/call flop. Turn you can lead, x/raise or x/call, tough I prefer one of the first.