I ran PIO sim on this hand, my Utg range 15% vs Btn flatter 26%. This is just theory trying to find the "baseline" and of course people are not playing like solvers.
Parametres:
My range:
https://i.imgur.com/Mrz2oeR.png
Btn range (might be too tight):
https://i.imgur.com/CMvD8do.png
Betting options:
https://i.imgur.com/HmkWK0s.png
Sim wants to check whole range on the flop, and never x-raise:
Btn should be polarizing their range on the turn with big bets but against this sizing, AK just continues x-calling.
River leading frequency for my range:
with AK:
River leading bluffs are 98 spades, T9s combos, small amount of TJs.
Against Btn´s shove AK folds around 60% of the time after leading.
So, by leading the river we are attacking against btn´s check back range which consists of AQ, AT, KT, K9, J9.
If btn overbluffs and/or valuetowns themselves by betting something like AQ,AT on the river, x-call becomes the superior play vs donking. Assuming Btn doesn´t overbet the river with QT like he should, we get same value without having to bet-fold our hand.