how does free will make sense without a soul?
it is the soul which in a sense is divorced from the physical determinations of corporeal existence, and thus is, according to those who believe in souls, able to make the choice.
It's the difference between what we call the külli will and the jüzzi will in maturidi theology, I.E: the divine will constrains the will of the human to be able to make a choice, even if said choices are ultimately divinely determined.
But if you subtract the soul from this, and I'm not sure how else one can believe in souls without it being the religious understanding of immaterial entities divorced from the world, then all choices are determined by material circumstance, not by divine will. Out of body experiences are irrelevant to this because it's a problem of method.
For instance, if you were to ignite cotton, both you setting it alite and it giving off the smell would be part of the divine will, it would only appear to you as autonomous. now with or without a soul, you could burn your finger with it, but the theory is such that in a cosmology grounded on souls, this is a free choice you make due to an intangible disposition provided to you by a divine creator. For true occasionalists, there is no reason why one can't just put their finger to burning cotton, because assuming it will always hurt is a denial of divine will. things-for-us do not exist in occasionalism, all that exists are what we are illuminated to see as sense impressions, but for a true occasionalist, sense impressions only exist within our mind. hence the idealist-materialist schism.
But without a soul, it's not a free choice, but purely determined, based on calculations one makes.