I think the reality may be more complex than simply citing the binary "free will vs determinism" as a reductive phrase.

Our brains are quite complex. My hypothesis is that we are matter and it is determinism...BUT... our brains also learn much like we saw with the advent of computers and now the evolution of AI.

What I mean by this is as we move through a day for example, and make choices.. those choices are not determined exactly as such because our supercomputer brain has looked far ahead much like a chess master reviewing all the possible moves and results from those moves and then makes a choice.

So as I go to work my brain is calculating the various routes I might take as well as evaluating whether I want to stop for coffee or not and then a result is determined from those choices based on the input data. As other new experiences occur they get added to the database and become new options or avoidences as the case may be.

So we do have determinism but the complexity of it provides what appears to be free will