It’s not even a well-defined question to ask "what is the best action".

To ask that in the context of a fight (not a bounded game like chess) is already to assume the existence of a complete utility function on which to measure it. That’s:

1. Philosophically, putting the cart before the horse.

2. Computationally, asking for the function that is the entire universe. Any utility function you define, an adversary (say, God) can find edge cases it doesn’t account for, endlessly. Chess has a finite state space; a fight doesn’t. Formalizing this hits the usual incompleteness and undecidability limits.

You’re claiming a perfect map exists (Platonist position); I’m saying that if such a thing exists, it’s just the territory itself, which isn’t a map (Nominalist position).