Forming simple epistemic logic formula from a given sentence

Question

Sentence: I don't know if I know whether Lionel Messi is the GOAT.

$a$: I/Myself
$φ$: Lionel Messi is the GOAT

Attempt 1: $\,\lnot K_{a}\,(K_{a}φ \, \lor K_{a}\lnotφ)$
Attempt 2: $\,\lnot K_{a} \,\to \, (K_{a}φ \, \lor K_{a}\lnotφ)$
Attempt 3: $\,\lnot K_{a}φ \,\to \, K_{a} \lnot K_{a}φ$

Which attempt is more accurate?

Answer 1

Yes! Knowing whether Messi is the GOAT or not means that you either know that he is the GOAT, or know that he is not the GOAT.