We can have "free will" all over the place, and it doesn't affect what God does or does not know. If you change you mind 20 times today about whether you will or will not go to the grocery store this evening, does God know what you will end up doing?
Yes, that's the point I'm making. Omniscience doesn't inherently mean free will or predetermination.
Omniscience doesn't equal double predestination. It also doesn't equal free will.
More steps are involved.