I recently covered this hand in one of my Drill of The Day's. Fun spot! π₯π
The river is a great card for the BTN's value range. By the time they bet all three streets, their range is heavily weighted toward strong value hands like trips, full houses, sets, and two pair.
While they can have some busted straight draws, most players don't pull the trigger often enough with bluffs to make calling profitable.
Against straightforward opponents, this is an easy exploitative fold with middle pair. Against loose, aggressive players who are capable of overbluffing, calling becomes much more attractive.
Always consider your opponent's tendencies rather than blindly following GTO.