Blinds 4 $0.25/$0.50
UTG Bifleur2019 $82.55
CO Epistolero87 $58.66
D monoculo $50
BB Hero $50
Preflop

Hero is BB$0.50 4
8cKc
2 folds, monoculo (BTN) raises to $1.25, Hero calls $0.75

Flop

$2.50
5s7cKd
Hero checks, monoculo (BTN) bets $0.75, Hero calls $0.75

Turn

$4
5s7cKd 8s
Hero checks, monoculo (BTN) bets $3, Hero raises to $11.50, monoculo (BTN) calls $8.50

River

$27
5s7cKd 8s5d
Hero checks, monoculo (BTN) goes all-in $36.50, Hero ???

vs good reg

flop - standard,
turn - x/r is fine, he calls with many worse 2 pairs and strong drows,
river - I think block bet 1/3 and fold is best play...
As played his range is pretty polarized - hi has exactly 9 value combos (streit goes all in on turn) KhKs,8d8h,7d7h,7d7s,7h7s,5h5c,Kh5h,8h5h,7h5h, potencial bluffs Ts9s, Qs6s, Js6s, Ts6s. Maybe more, depends how many flush drows he calls on turn.

However, even if I have the best bluff catcher, I think I can fold. He can bluff easily with smaller sizing, because my range is capped and he has fold equity vs my miss drow give ups. Or is this thinking too nitty?

Thank you :)