The body is full of reflexes that people attribute to skill.

I’m not sure how this is relevant. So the body is full of reflexes - so what?

If you had free will, you’d be able to will yourself to stop breathing and die but you cannot.

You’ll have to justify this conclusion further. I don’t agree that an instinct for self-preservation necessarily means that free will is an illusion. Again, my point is that part of “free will” may extend beyond the conscious into the sub- and un-conscious. Therefore, even if “I” unconsciously choose to continue breathing and not die, that is still “I” making that decision, regardless of whether I consciously recognize that decision or not.

The brain has tricked itself

This I certainly acknowledge is a possibility, the mind tends to construct narratives and justifications as a matter of course. However, this again does not preclude the possibility of free will.

That is, just because the mind tricks itself sometimes does not mean that it does so always, and that this accounts for all observed human behavior in all cases.

into believing it is more than it is despite mounting evidence.

If you are going to cite “evidence”, please present it.