Discussion: The question of whether we have free will is related to the question of whether we live in a simulation. Surprisingly! Neither claim can be proved. (Yes or No)

If we have free will, we (ostensibly) do not live in a simulation. The great philosophers (including physicists) face the question but always return to the starting point! The fact that a clear answer cannot be obtained is reminiscent of Alan Turing's halting problem and the incomplete mathematical argument developed by the Austrian philosopher Kurt Godel.

What does proving or disproving that we live in a computer simulation take?
The answer to this question seems very simple; it is clear that we live with free will. Leading scientists, philosophers, and physicists have dealt with this question for years without unequivocal conclusions.
The simulation theory will fail if you can locate an event, nature show, behavior, emotions, natural processes, etc., that does not have a mathematical solution with a workable result! The premise is that all natural processes can have a distinct mathematical expression. If you search, you will find it challenging to shatter this claim! All-natural functions behave exemplary and surprisingly with complex mathematics that optimizes resource utilization.

What does it take to prove that we live in a computer simulation?
It is impossible to prove that we live in a computer simulation from our system. The question is very similar to the halting problem posed by Alan Turing. The conclusion is that this question has no solution. (Logical limitation)

To prove unequivocally that we live in a simulation, one of two things must happen:
Intelligent aliens will appear on Earth and show us convincing arguments that we live in a simulation.
We will crack the riddle of the universe, and we will be able to find the simulation formulas at a level where we can predict events with probabilities that do not leave a doubt of randomness.
At the moment, neither option looks pretty close. In my opinion, currently, the first option is more reasonable than the second. (Just an intelligent and unscientific guess.)

At the theoretical level, is computing power strong enough to simulate all human beings simultaneously?
The answer concerns the nature of the simulation. Assuming that simulation controls only significant milestones in our lives and not every second and every marginal decision, the answer is "yes." The computing power required is enormous but probably possible on a theoretical level.

Links:
Deterministic human simulation—Pinnacle of scientific achievements.
https://www.sf-healing.com/page/245 (Copy & Paste)

The essence of life and free will — Philosophical Thoughts.
https://www.sf-healing.com/blog/post/153 (Copy & Paste)