There's no good reason to believe in the metaphysical.

For all intents and purposes there is only the physical that we know about, and the physical yet to be discovered.

There's no reason to believe that the brain is therefore anything other than an evolved machine entirely governed by the laws of physics.

Physics allows for degrees of determinism, and degrees of non-determinism through quantum physics, but particles don't think. Even in situations of quantum randomness, the probability distribution matches mathematical formula, it doesn't make intelligent choices.

You can't combine these all these effects that follow exact laws and combine them together into an assembly that somehow isn't bound and determined by these laws.

What we choose to do is a purely mechanical result of sensory impulses interacting with the current state of our brain to move it to a new state.

We are robots, but for the large part each and every one of us has constantly changing programming that is so complex that the actions of an individual cannot be predicted, nor can the programming be modified by others, so we can't be exploited like a robot.

So in practice it rarely matters that we don't have free will. Though I do think it's important to remember that people are a physical phenomenon especially when judging and making demands of others, because it allows you to question whether that particular person is capable of making the improvements that you want them to under the particular state and conditions they're currently in.