So I made a bunch of big blunders here but I'm curious about how I should have played the turn.

This is on Global Poker NL10 with 8 players

UTG2 Raises 0.35
Folds to me in MP2, I make a loose call with As6s
CO Calls
SB Calls
BB Folds

Pot 1.5

Flop: 6h 9s Ah

Everyone checks including me (I thought CO would bet behind me but I guess the multiway pot made him check instead)

Turn: 2h
check
check
I bet pot (1.5) trying to correct my flop mistake on a board that can now potentially complete a flush on the river.

everyone folds

My main question here is about my turn bet size. I realize I made a loose call preflop, and I think I should have leaned towards a bet on the flop (I guess I was trying to mix it up but chose a bad spot to do it).

Regarding the turn bet, a smaller size might have built value and minimized losses vs. a made flush, but a bigger size denies equity to straight draws and river flushes. I also think a small turn bet size would have put me in a tough spot if someone did call and then raised me on the river. I wasn't sure which size to pick. There are 2 straight draws on this board and if someone had a heart in hand I didn't want to give them favorable odds. I'm confused about what bet size is ideal here, should I maybe have even overbet?

Greetings ventrolloquist.

I will try to explain the hand, and clarify your doubts. To start you have to think that the ColdCall ranges in MP must be very tight, to have hands of the type Axs calling in MP is to lose money and get into complicated situations, just fold.

In the Flop we have double couples, which may seem very good to us, but before making a decision we must take into account that this flop opens color projects, and between 9 and 6 there are staircase projects things that you have to have very when we play boats with multiple players. What should we do? In general I think that check / call is the best move, if we bet they will match us with enough hands and on the Turn there will be many cards that do not benefit us, any card that completes the color project or any 7 or 8 are cards that we do not want to see, for that reason we must check and in the case that CO bet we would call.

Now the Turn, the color project is completed, and you decide to bet the whole pot, to do this you have to think, what worse hands are going to match you? In general I think that bet was very bad, the hands that go behind to fold and call will match you only with colors, with color project, A9x would also match you, some sets of 99 or 66 would also match you.

I think I explained enough, in general, the first thing you have to do is have well-defined pre-flop ranges, which when we play at low limits is very important, then only then think about your post-flop game.

Greetings.

I agree with everything Girfied said about your preflop range, and with 1 more to add.
You shouldn't correct a mistake with another mistake, it's like telling your wife a lie with a bigger lie, that will never end well.
Also, if you make it a habit of doing so, you are in deep trouble in future.

You might be lucky this time that everyone believed your lie but someday somehow, you gonna meet the big bad wolf.
Check the turn and let it run, worst case is you only lose 0.35 for making a post-flop mistake.

Thanks for the pointers guys.

ps: the Ax suited call is something I only did because I knew a multiway pot was highly likely. I know the UTG opening range has me dominated but I figured if he hits a high card and I hit a monster or a flush draw I would be payed more than I would risk in the long run. Was this a bad assumption? I guess suited connectors would have been better to call with here, but what about A6 suited?

Call with A6s is not that bad actually by default, but it is bad at NL10 where rake is very big, although I don't know about GG network? How big is rake there?

Flop, you definitely should bet small bet, like 33% or 50%. No reason to slowplay and expect others to bet, because multiway they won't bet lightly.

On the turn, by betting so big you are actually putting yourself in tough situation, because now you are forcing everybody to call you only with with very strong hands, like flush or set. You won't to charge Ax hands, but when you bet so big all Ax hands can easily fold. Correct bet sizing would be around 66% pot.