I've recently come to the conclusion that I know very little about the mathematics behind working out GTO strategies, and I would like to change this.

I am struggling mainly with river raises. Here is a hand I played recently we can use an example:

BTN: $250.00
Hero (SB): $776.27
BB: $507.28
UTG: $257.50
MP: $348.04
CO: $976.73

Pre Flop: ($7.50) Hero is SB with Ah Kh
4 folds, Hero raises to $15, BB calls $10

Flop: ($30.00) Ks 2c 8d (2 players)
Hero bets $20, BB calls $20

Turn: ($70.00) Td (2 players)
Hero bets $47.50, BB calls $47.50

River: ($165.00) 8h (2 players)
Hero bets $125, BB raises to $424.78 all in

As I understand it, if I had a good read on Villain that he plays very straight forward and would never run a bluff in this spot, or a predisposed generalisation on the player pool at these stakes; which would be that they don't bluff-raise rivers nearly enough to be balanced/ optimal, then I can employ a max-eploit strategy and fold a lot tighter than otherwise. This obviously holds true too if I'm playing a maniac button-clicker, where I can call lighter than otherwise.

But if me and villain were both employing GTO strategies, then how would I go about working out what the minimum hand I want to be calling with in this spot is?