ok im not sure so I decided to go for deeper analysis.
Lets assume hero bets 1/2 psb. hand is 3way and we dont know opponents so assume there will be tight and loose continuing ranges. we give the sandwiched guy the tight range of
($FI50!AA): QQ+, Qcc+,68cc+
CO will fold ~60% of his entire range and continue with ~40%. Now BU will call somewhat looser if Co folds and he is last to act. lets say he continues with
($FI50!AA): QQ+,cc, 68:cc, 468, 7+:36+
BU continues around ~48%. alltogether your half pscbet needs to woork 1 of 3 times and I dont see that happening so at very first your cbet wont autoprofit.
so if you dont bet for value or because you have foldequity I cant really see why you are betting. the other problem is your playabaility on further streets.
if you dont improve but continue small you will likely get called another street, if you continue big (I would bet less than 1/2 ps on flop if you have the plan to bet bigger on turn if only get called) on turn, get called and improve river you will play a flush on a paired board OOP and I dont see how a PLO player can like that scenario.
if you check the turn you can only hope for check behind of villains because you cant continue on big bets and small bets might be a trap, esecially because 755 flop is already well enough connected to let someone have a boat.
I dont know I mean Im sure I find more reasons to not cbet the flop but if you really think they will fold often enough yo can go the safe route and 1/3rd the flop IMHO