Not that I agree with your premise, but why would you personally adopt a cognitive dissonance? A healthy mind is generally regarded as satisfied with itself as it is free of self-contradictions.
I think behaving as if there is no free will is such a change from how I was raised and how 99.99% of society believes and functions, would require some Buddha-level strength of will, which I don't possess.
It's so different than all the constructs we've created, you can kind of throw "generally regarded" out the window, frankly :) (don't mean that to sound harsh if it does). All of psychology would need to be rewritten. By me? I guess?
The 3rd option is to try and convince myself of what I regard as a lie (that we have free will), which is also difficult, but probably easier?
