Well, u maybe right to question:

Therefore, if what we do has been destined by God, then God cannot blame us for our sins because He is the one who has decided our actions, including sinning.

I believe that God is just. The check and balance of our life will remain the same even if we end up in Hell.

If we are destined to be in hell because of our wrong doings in our lives, it's gonna be a fair game because God already gives us the pleasure when we commit all the wrong doings.

If we study how the prophets before this such as Moses, Jesus and Mohammad, though they will end up in paradise, but look at their lifetime. They suffered so much from the oppositions.