“There is no real way to separate ourselves from God, I think.” YES. To “separate” ourselves from God would be to cease to exist.
God is omnipotent, omniscient, omnipresent, and omnibenevolent. We cannot “escape” his will for us, but that doesn’t mean we have no free will at all. We have some choices in our lives. We cooperate with God’s will, we do not compete against it. We do not choose to be born, we do not choose our bodies, our parents, our times, our communities, etc. However, we choose who we become as persons (though God knows and wills this too).
God has always known and willed us to be either evil or good, and it is fair for him to punish or reward us to the extent that we have freedom. We must have enough freedom to actually do what is right or what is wrong, or else there is no such thing as justice. It is impossible to fully understand this mystery of how God can be totally sovereign and we can be free simultaneously, and yet it must be so. Because we are blind, we are free.
My advice would be to try to focus on doing the right thing. If it turns out you never had free will, and God is both good and just, you have nothing to fear. If it turns out you never had free will and God doesn’t exist, you still have nothing to fear. If it turns out you do have free will and God exists, trying your hardest to do the right thing can’t hurt your case. If it turns out you have free will but God doesn’t exist, you can at least be comforted by the thought that you are a truly good and honorable human being who has left your tiny slice of existence slightly better than when you came into it.