PLO10 QJT9 in BB

You can't donk the flop because it's a draw heavy board. You think you have a nice hand but you don't really.

You have 10 outs to the nuts which means there are 32 bad cards for you and 2 cards that may or may not be good (the jacks). If you donk and get called you have to check 75% of turn cards and when you do, villain will bet the pot and you have to fold. So by donking this flop you are simply bloating it for someone else to take off you on a later street.

If it was a rainbow board then with your additional outs to the nuts, donking or checkraising the flop would both be fine.

As for the turn, well it helps you a little but you are out of position against 2 opponents. It's unlikely you will get paid if you hit because it's a super draw heavy board and check/calling the turn screams a draw. If you don't improve on the river you will definitely be folding to a river bet so look at how many cards you can hit. Probably around 15 cards, a third of the deck (usually spades will be good, sometimes it wont however).

In a vacuum you can argue that the turn call is slightly +EV however there is a lot of reverse implied odds on the river (where you pay off your opponent if you hit a straight on a heart board ,you hit a jack and pay off villain who has a straight or you hit a flush against a bigger flush). When you improve, villain is unlikely to pay you off since it's obvious you are on a draw (as we saw on this river) so there aren't many good reasons for calling this turn bet.

As for the river, you were absolutely right to bet full pot, if villain does have 47 or 79 then he might just make a crying call. If he has anything else (like a set or top 2 pair, then it's a trivially easy fold for him no matter how much you bet).