Plugged it into the solver, and doodoo was more right than I suspected.
Game tree was:
OOP player can just bet .75 PSB
IP bets either .33 PSB or .5 PSB on flop, .6 PSB or 1.5 PSB on turn, then .75 or 1.5 PSB on river
Here's what it does OTF:
https://imgur.com/a/XPXwgjH
As you can see, it mostly prefers the half pot sizing, and bets 8c7c. It prefers the 1/2 PSB, but mixes in x's and the smaller bet too
OTT assuming OOP player calls, it has no overbet range. It bets half the time with 8c7c
https://imgur.com/a/XU0ivGt
OTR it pretty much just overbets. It uses flushes, and some hands like 88, 77, 66 with a spade, along with Ks9x. It just gives up with 8c7c