This may be a stupid question, but has "free will doesn't exist and determinism is false" ever been brought forth or explored as a position in philosophy?
Galen Strawson (of ‘most famous father-son duo in philosophy’ fame) has, in a sense (his position is actually that free will is incompatible with
both determinism and indeterminism, and so it’s completely impossible).
Speaking more generally, one way this position could come about is by agreeing with a point that many compatibilists have made, and that I gestured towards in my post directly below the one you quoted, namely that free will may actually
require determinism in some sense. Unlike the compatibilists though, such a philosopher would then say that determinism is in fact
false, and thus that free will doesn’t exist. Their picture of the world would be one in which human action happens completely randomly and spontaneously, depriving us of any meaningful control over what we decide to do.