A few experiments have quietly rearranged how I think about free will.
In one, a neurosurgeon operating on a conscious patient stimulates a spot in the brain that makes the patient's arm move. Asked why they moved it, the patient doesn't say "you made me" — they say they wanted to. Do it again, and they invent a fresh reason again. The explanation arrives after the action, and it always feels like a decision. There's also a body of work suggesting the electrical signal for a movement appears in the brain before it reaches the regions we associate with conscious thought — the choice seems to be made before "you" know about it.
Then there's anosognosia, usually caused by a stroke, where people flatly deny facts about their own bodies. One woman insisted her paralyzed right arm worked fine; asked to move it, she'd produce excuse after excuse. In a striking test, doctors said they were anesthetizing her (already paralyzed) right arm — really a placebo — and she reported it now felt paralyzed; when they "anesthetized" her good left arm, she said that one had stopped working. The mind will confabulate a coherent story rather than admit it isn't in control.
I hold these as anecdotes more than proof — I can't always reconstruct the exact details — but together they point somewhere uncomfortable. The narrator in your head is very good at taking credit for decisions it may not be making. The line on free will I've never been able to shake is "free will is the ability to gladly do what I must." We act as if we're steering, even when the wheel may not be connected to anything.