Advice on implementing highly mixed spots

When learning to play OOP, I notice that a lot of spots are highly mixed and difficult to implement. I often struggle to extract relevant heuristics when studying them because of the complexity. For example, analyzing below HH left me really confused in terms of how the OOP player should approach this spot.

10NL Fast Fold, SB vs UTG 3BP

Flop (25bb): Td 4d 2c
Bet 15bb; call

Turn (55bb): 8h
Bet 30bb; call

River (115bb): Qs
All-in; call

Cbet strategy for OOP on the flop is very difficult for me to understand because the entire range equally mixes check, B50, and B75. It also seems that a pretty significant portion of the range will triple barrel - including bluffs like A5s and KJs. ATs also jams the river, which I guess is kind of a value-bluff against weaker Tx that would call (only in GTO probably), but I don't really understand the benefit here with an overcard coming in on the river.

I guess to sum up my questions:

- How should I approach studying & implementing highly mixed spots?

- Why is the above example a good spot to barrel down? How can I identify similar spots in the future?

- Is there any general framework/approach I can utilize to simply/help myself understand these spots better?