How to play this hand multiway?

Bet the flop. Preflop could easily have been a misclick, but it's pretty unlikely to be a strong hand. If it were a strong hand he'd also likely bet this flop as no-one is betting an AK flop behind him in a 3b pot without a good hand. You don't have to bet big, but there is a K-high flush draw to protect against, and their ranges simply aren't strong given action.

Bet 10bbs, have them all call, Td on the turn, gogogogogo

Yeah, good point. Given the action, AA is super unlikely, as is KK. Betting small on the flop seems better.

Flop bets seem standard, not sure on best sizing - small, medium and large all seem good (and we can even put a little extra pressure on UTG by betting half of SB's remaining stack so action can re-open over jam.

Bet the turn 21 - 25bb, betting around 10bb or half of SB's stack are both quite terrible, this hand should be played for ALL of the chips vs any of the players when it has played that passively so far. Betting small guarantees that you can't stack the deeper stacks barring a massive overplay from a lower flush (that will just x/c twice all-in anyway vs larger bets) or a low frequency psychotic bluff (likely <2% of the time.)

What are you talking about that you can't get 2 streets of value? If you just get called on the turn the river is the easiest all-in in the world vs either UTG or BB on a non-board pair. I might be a bit concerned on board pairs since both limp cold overcalling a 3bet UTG and cold calling a 3bet in the BB vs SB are high frequency ways to play KK from donk players which is the entire player pool at 10PLO on Ignition. I also expect that either player will donk shove into you if they boat up though so when checked to on a board pair river you should still be value shoving the Q flush unless you have noticed either player to have played a hand incredibly trappily before that. By incredibly trappily I mean something like they flopped the nut flush OOP in a SRP, x/called a medium bet, then checked turn and river when the nuts didn't change.

If you bet large and face a turn x/c and then donk pot on a blank river I would lolfold, this will be a terribly played K high NF > 90% of the time.

Thank you. I think I have a habit of playing too passively in general, and especially with non-nut flushes. However, on this board, I can easily get value from sets and random 2 pair.