There are universes where free will doesn't exist.
They are similar to getting on a roller coaster.
You get on, have the experience, you get off.

Our universe is very much designed around free choice.

Think of it this way.
Whether aliens exist or not
If the planet decided to not believe in aliens we would shift to a phase where we would never interact with aliens. They could be right next to us, and cause things to happen in our environment, but we would constantly find alternative explanation for each thing that happened.

And from my experience, if God wanted everyone to believe in God, everyone would believe in God. It would be impossible to do otherwise. It would be even worse than questioning gravity.

Thanks for the comment elsewhere.