There's an element of free will and an element of instinct and mechanism.

Conceptually I see the mind as a system which takes its own outputs as inputs and also reacts to externalities. I also believe in a stochastic universe so there's plenty of opportunities for these partially self-decided decisions to be unique, unpredictable and incorporating the sense of self and an introspected mental model. This is a "good enough for me" version of free will in a physical system.

I have some intuition that the brain probably undergoes some level of "cognitive bootstrapping" where at some point it goes beyond just being a mechanism and starts reacting to stimuli as according to its own learned mental model. But this is necessarily limited and the degree to which an individual gets to do this, as opposed to reacting instinctively or reflexively, varies based on their physical and mental state.

There are also instances where an individual loses their personal sense of freed will and submits it to a crowd, such as in the concept of "de-individuation"