Should've folded A5o UTG.
The flop was bad for your hand, and you're multiway out of position against a calling station. Don't cbet, just check/fold.
The turn did nothing, and calling station will continue to call. Still check/fold.
The river continues to change nothing. Still check/fold. If he was on a heart draw, the river goes check check and you win with A high anyways. You're very lucky you didn't get called down.
You don't have to do anything fancy to beat 2NL. You don't need to steal blinds with trash, you don't need to multi-barrel bluff, you don't need to 3bet light, and you don't need to value bet thin.
Open quality starting hands in position preflop. If you miss the flop and you're heads up, cbet the flop. Give up on the turn if you don't improve. If you hit top pair or better, value bet all 3 streets. If you get raised by a loose-passive fish on the turn or river, fold anything less than trips with a good kicker.
Don't be fancy
Microstakes is all about hitting top pair + good kicker or better and getting maximum value.