Basically run this every which way including with what would be considered pretty "conventional" ranges and it's a pretty common theme that 1bb is optimal flop sizing, and I think you'd be hard-pressed to find any configurations where that's not the case for OOP player, that 1bb sizing is just super powerful here, there's not much else to say. I'll try to dig up some of the posts where I try to sift through that phenomenon but I think it boils down to what that monochrome texture means for our air--it means any hand of V's that has no diamond will be hard pressed to realize its equity such that OOP player's air is highly incentivized to go for cheap bluffs and even more importantly just keep the range merged heading to the turn--OOPs value is fine with this because even flushes, which heavily block worse that'll continue (like worse flushes and flush draws), are fine being cbet for 1bb in fact it's just a consistent result that 1bb is highest EV cbet sizing and there really aren't any close competitors either.
Narrowing IPs range only has the effect of forcing OOP to check progressively more combos in lieu of cbetting but it has no effect on sizing.
Will post screenshots of my tree after my session today--at the end of the day, sure you're right that these models have their limitations but the way the game works is you kind of have to have justified reasons to reject them, because absent a read, you really have no idea what your opponent is doing and these models do an excellent job at predicting what's hidden from us.
So I think having the tree screenshots would help--it'll make it easier to formulate ideas on what his range is because we'll have a good reference (the equilibrium) for comparing to what we think the population is actually doing.
This spot is absolutely not a trivial flop give up though.
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#TreeBuilding#V2
#Range0#AA,KK,QQ,JJ,TT,99,88,77,66,55,44:0.5,33:0. 1,22:0.1,AK,AQ,AJ,ATs,ATo:0.5,A9s,A9o:0.1,A8s,A8o: 0.1,A7s,A6s:0.5,A5s,A4s:0.5,A3s:0.5,A2s:0.1,KQ,KJs ,KJo:0.5,KTs,KTo:0.1,K9s:0.5,K8s:0.1,K7s:0.1,QJs,Q Jo:0.1,QTs,Q9s:0.6,Q8s:0.1,JTs,J9s:0.1,J8s:0.1,T9s :0.5,T8s:0.1,98s:0.5,97s:0.1,87s:0.1,76s:0.1
#Range1#QQ:0.5,JJ:0.5,TT:0.5,99:0.9,88:0.9,77:0.9, 66:0.9,55:0.9,44:0.9,33:0.9,22:0.9,AK:0.5,AQs:0.5, AQo:0.9,AJ:0.9,AT:0.9,A9s:0.9,A9o:0.5,A8s:0.9,A8o: 0.1,A7s:0.9,A7o:0.1,A6s,A5s:0.9,A5o:0.1,A4s,A3s,A2 s:0.5,KQ:0.9,KJs:0.9,KJo,KTs:0.9,KTo:0.1,K9s,K8s:0 .5,K7s:0.5,K6s:0.1,K5s:0.1,K4s:0.1,K3s:0.1,QJs:0.9 ,QJo:0.5,QTs:0.9,QTo:0.1,Q9s:0.5,Q8s:0.5,Q7s:0.1,Q 6s:0.1,JTs,JTo:0.1,J9s:0.5,J8s:0.1,J7s:0.1,T9s,T8s :0.5,T7s:0.1,98s,97s:0.5,96s:0.1,87s,86s:0.5,85s:0 .1,76s,75s:0.5,65s,54s
#Board#5d 6d 2d
#Pot#650
#EffectiveStacks#3621
#AllinThreshold#67
#AddAllinOnlyIfLessThanThisTimesThePot#500
#MinimumBetsize#100
#FlopConfig.BetSize#10, 33, 66, 100, 150, allin
#FlopConfig.RaiseSize#50, 100, allin
#TurnConfig.BetSize#10, 33, 66, 100, 150, allin
#TurnConfig.RaiseSize#50, 100, allin
#TurnConfig.DonkBetSize#10, 33, 66, 100, 150, allin
#RiverConfig.BetSize#10, 33, 66, 100, 150, allin
#RiverConfig.RaiseSize#50, 100, allin
#RiverConfig.DonkBetSize#10, 33, 66, 100, 150, allin
#FlopConfigIP.BetSize#10, 33, 66, 100, 150, allin
#FlopConfigIP.RaiseSize#50, 100, allin
#TurnConfigIP.BetSize#10, 33, 66, 100, 150, allin
#TurnConfigIP.RaiseSize#2x, 50, 100, allin
#RiverConfigIP.BetSize#10, 33, 66, 100, 150, allin
#RiverConfigIP.RaiseSize#50, 100, allin