Hello! New to this site. Started playing NLHE back in the 2000s growing up, until around 2011. Just recently started again in Feb this year and looking on how to improve. I've only played a few thousand hands in the last month and can't seem to really gain any ground.

I started on ACR, playing NL2 and did ok on it but was still loosing. Moved to ignition NL5, done mediocre. Started Sit n Gos and I've cashed and won a few, but also lost more than won. I've played around 5 low stakes tourney's and finished in the money in two, one finishing in 7th. I've started studying more, reading Mastering Small Stakes No Limit book, about half way through. Studied charts as well and have a good understanding of GTO. I have around 1400 hands in cash, around 900 in tourneys since I started in February

I have a hand I recently played that I'm not sure I played correctly, and this would sum up a lot of hands I find myself in.
On the CO with AJs diamonds, UTG raises 2bb, action folds to me and I call, SB/BB calls
flop Tc Ah 8h
UTG cbets half pot, I call and BB call
Turn 5c
BB check, UTG bets half the pot, I call, BB folds
River 8d
UTG bets just under the pot, putting me all in, where I fold.
Is that a spot where I should have maybe 3 bet pre flop, or raise the UTG bet? If not, was it just a call to showdown or was folding turn/river the better play?

Is my value betting off? Do I not 3bet enough?

Thank you for the help and suggestions!