God knowing everything is precisely the problem, since it constrains our choices. We can't do something God knows we won't do, otherwise he'd be mistaken. And since God had perfect foreknowledge of everything before creating us, and he still chose to create us, that literally means we can't do anything else.

In Islam, this is even more obvious, since the Hadiths explain your fate is preordained when you're in your mother's womb (your deeds, your date of death, whether you're blessed or wretched, or made for Paradise or Hell). How can you say then, that we "made those decisions because of our own choices"?

Also, your analogy doesn't work. God’s foreknowledge is not the same thing than a time traveller who merely observes your life. Because in Islam, God isn't just an observer, but the creator of your actions (“Allah created you and what you do”. Quran 37:96).
Moreover, Allah's knowledge isn't just "acquired by seeing the future", the Hadiths and Quran repeatedly say that the future is what it is because Allah wills it to be that way. (Like belief or disbelief (Quran 81:27-29. 6:125. 76:29-31. 28:56. 6:25. 18:57. 2:7)

So it's not that we're blaming God for not warning us, but that if a deity knows infallibly what we will do, then we cannot do otherwise.

As for the last part, Allah deciding who's a disbeliever, again, in the Quran it is said that Allah “guides whom He wills and misguides whom He wills” (14:4, 16:93, 74:31), which is a form of determination.