The way people talk about it makes it sound indistinguishable from "random will". If you believe in the existence of a "self" in any form, be it the chemical signals and electrical impulses in your material brain, or a ghost existing outside of space and time controlling your body like a puppeteer, you must believe in one of you believe in that self having free will.
Say you were to run a scenario many times on the same person, perfectly resetting every single measurable thing including that person's memory. If you observe them doing the same thing each time then they don't have this quality of free will? But if you do different things each time are you really "yourself"? How are your choices changed in a way that preserves an idea of a "self" and isn't just a dice roll? Doesn't that put an idea of free will in contradiction with itself?
Edit: I found this article that says what I was trying to say in much gooder words
I'll open it up to anyone to follow up on recommendations because I might be a little over the top with it...I like to read the old texts in the original or plain translation. The Mūlamadhyamakakārikā by Nāgārjuna is what I was thinking of when I wrote up my comment.
I would say to find a translation and commentary (the wiki page has a list), and maybe also watch some video lectures before starting because the Buddhist philosophical tradition is its own beast that you would need context for
I'll see if I can follow up with some video links later