"Free Will" doesn't make sense as a concept, or at best, is a cognitive illusion, stemming from ignorance (our inability to see/compute the entire causality chain leading to an event). Our legal systems, cultural systems of morality, and systems of self-regulation are founded on the assumption of free will, but being founded upon a false precept, they aren't as effective (in getting us what we want) as they could be if they were based on objective truth.
(I put "Free Will" in quotes, because it begs definition, which I'm not doing here, and so, just vaguely alluding to the folk notion of Free Will).
"Free Will" is a commonly accepted belief, and I adopted it unquestioningly / unthinkingly (as one does with most memes during childhood, particularly since I grew up in a somewhat Catholic household). At some point in the last few years, cracks began to form in that belief. For a while now, I have "rationally accepted" that free will isn't a thing, but hadn't really integrated it into my beliefs (like one can recite a mathematical equation without any "intuitive" understanding of its ramifications). Slowly, that's been changing, and causing a resulting domino effect on how I view others (and judge, and interact, etc.). Generally, resulting in more compassion. ...and agency, both in my interactions with others and with myself. (Yes, no-free-will is still compatible with a notion of agency).
I've been meaning to write about this, but the following Sam Harris podcast, though perhaps not up to the ultimate philosophical standards, does a better job at explaining than I probably would:
First half: https://youtu.be/u45SP7XvoU?si=ry3c8nw3lD3TOxi
Entire thing (requires email registration): https://www.samharris.org/episode/SE801D247DE