From an adaptation standpoint, it occurs to me that true arbitrary free will, separate from thought processes such as the weighing of risks and benefits, would be an extraordinarily dangerous (and disadvantageous) trait.
Hundreds of times of day, I face situations where it would take only a few seconds of simple voluntary action to do myself in. There are balconies and stairs I could fling myself off of, poisons I could ingest, simple turns of the steering wheel that would quickly result in a fiery crash. And that's just one extreme. It would take me little time or effort to commit a foolish crime for which I'd quickly be caught, take actions at work that would get me immediately fired, or act so as to ruin my marriage, lose all my money, or burn down my home.
On those occasions when someone actually does something like that, we don't say, "Wow, that guy who smashed a jewelry store window in broad daylight with a cop standing right nearby must have had unusually strong (or unusually free) will." Quite the opposite. We speak of the "uncontrollable impulses" of a mental disorder.
It might be helpful to attempt an operational understanding of cognition related to the internal narrative of free will. What kinds of decisions and behaviors do we most associate with exhibiting or acting upon free will? How are those decisions and behaviors advantageous relative to alternative automatic, habitual, routine, or rote behaviors that would seem to involve less cognitive effort? What cognitive mechanisms are necessary to reliably result in the more advantageous behavior more of the time?