Have you come across research/evidence that a neuron can fire spontaneously, without sensory input from the outside world and without being triggered by another neuron via neurotransmitters? If so, then you're right, there is free will, but I have yet to come across any such evidence.

“We must believe in free will, we have no choice.” — Isaac Bashevis Singerz

On the other hand, if free will does not exist, there are certain benefits as well. For example, forgiveness would be a given, since bad actors do what they do out of compulsion, not of choice. One can take necessary actions to prevent them from doing further harm (ex: lock up the criminal) without anger and without the desire to punish out of the desire to retribute.

https://www.lifeisloveschool.com/DidAbusivePeopleChooseToHarmUs