It would seem that instead of omnipotence, you meant omniscience.
I believe the future is deterministic, and yet I believe in free will. I suppose at first glance it seems a contradiction, although God may see the endgame, there is no reason to suppose you don't have control of your decisions now, even though there is a definite and determinable decision you will make.
The standard argument against free will, according to philosopher J. J. C. Smart focuses on the implications of determinism for 'free will'. However, he suggests free will is denied whether determinism is true or not. On one hand, if determinism is true, all our actions are predicted and we are assumed not to be free; on the other hand, if determinism is false, our actions are presumed to be random and as such we do not seem free because we had no part in controlling what happened.
https://en.wikipedia.org/wiki/Determinism#With_free_willAs for the common painting of God as evil, it's getting old. God has created an absolute moral system, which is really the only kind that works. Flimsy preferential morals do not work.
The existence of hell is in line with the view of a Just creator, not simply a creator who wants everyone to be happy.
@ktttn
Theists actually vary on whether or not there is a hell, some would say not. Theism simply means there is a God and does not go much into depth after that.