My recommendation is to deny the concept of free will at a deeper level. It doesn’t matter whether physics is deterministic or indeterministic or even whether or not humans have immaterial souls; the concept of free will is itself incoherent. It could not be had by any possible being in any possible world.
The crucial question: To what degree are a person’s actions determined by the state of his or her mind?
This state includes but is not limited to a person’s nature, personality, preferences, knowledge, skills, and memories. These, I assume, can be agreed to exist whatever the actual metaphysical basis of human consciousness.
To the extent that human actions are predictable, we predict them based on our knowledge of the mental states of the actors. This is evidence, should any be required, that the mental states of human beings affect their actions. In other words, mental states partly determine human behavior.
To the extent that such states determine a person’s behavior, this behavior is not free, for to that extent it could not possibly have been otherwise.
To the extent that such states do not determine a person’s behavior, this behavior is meaningless, for to that extent it is independent of everything that determines who that person is.
Is free will the ability to perform meaningless actions?
This is intended as a rhetorical argument rather than a strictly logical one, for its conceptual incoherence makes free will difficult to describe in logical terms. I can see places to quibble with my reasoning, but this is essentially the argument that changed my mind on the issue.
The primary counterargument I have encountered is that there is some fundamental property of human agency that cannot be subsumed under nature, personality, preferences, knowledge, skills, memories, or anything else along those descriptive lines. I can only reply that whatever remains behind when everything of importance has been stripped away must be of minimal worth.