Ignoring the pre-flop action and without any stats on the UTG player, flop either option is reasonable, turn call is fine and I think this is a fairly close river spot but a fold. OP has fully polarized his range, and while at some higher stakes I think players could be potting JJ9 and J9 combos to specifically push off chops, at 1/2 I think this is either air/missed flush draw or the nuts the majority of the time. Qd is a terrible card to have in your hand at the river blocking a number of villains bluffs. Someone can run this through a solver but my gut says bluff catch here when your rundown isn't blocking flushes, fold when it is.

In general in PLO, calling down with second nuts is going to cost you a lot more than it will make

pot / pot into two opponents is definitely showing a lot of strength

Agree that pot/pot/pot into 2 opponents shows strength. On the flop, he can easily have a set or 2pair or a wrap with a big flush draw. Once the straight hits, and villain has 2 opponents and keeps betting pot, then they tend to have set+big fd+gutter or nuts+redraw or just nuts. When he pots the river yet again, into 2 players, they just tend to have it. I guess it could be AA or QQ with nut flush draw, with villain betting the blockers. But my experience of calling for that reason when villain pots into 2 players, is that I get shown the nuts.