Yes it seems like I missed one aspect of your question, apologies for that.
There are two different but related things that we are discussing here:
1.That God knows our fate.
2.That God guides those who He wants
I think I addressed the first point in my original answer. There I wrote that God knowing our fate does not mean that he formulates it no matter what we do. Rather it simply means that He (the All Knowing) knows where we will end up.
However let me bring another important point to our attention as well.
Do we consider God to be limited by time or do we consider time itself to be created by God? I think the one God that we know, as introduced in the Qur’an, is the perfect being that has created every other thing. This includes the dimension of time.
If we appreciate the above then we can also appreciate that the question you asked and the answer I gave above both are suffering from a flaw, that is, both the question and the answer assume time dimension for the Almighty. We cannot blame ourselves for this flaw of course as we can only talk from our own limited perspective. When we say He has written our destiny we are saying that sometime in the past, God wrote what will happen in future. We should appreciate (though we cannot fully comprehend) that for the Almighty, past, present and future are irrelevant. Thinking about it from this perspective, the question will not even raise.
As for the second point, that is God’s guidance, you are correct in saying that the Qur’an informs us that we cannot reach salvation unless God blesses us with his guidance. There is no question about this. The question however is whether God makes His choice randomly, on the basis of an unfair criterion or on the basis of a fair criterion.
The Qur’an advises us that it is Zalemeen (2:285), Kafereen (2:264), Faseqeen (5:108), Musrif and Kazzab (4:28) and groups like these who God does not guide. In other words, God does not guide those who do not deserve this guidance. This means God makes His choice on the basis of fair criteria that directly relates to our own performance and attitude.
Therefore while it is correct (according to the Qur’an) that no one can reach salvation unless God guides him, it is not correct (according to the Qur’an) to say it does not matter what we do as God decides who to guide. The correct understanding is that it definitely matters what we do because it is based on this that God blesses us with (or deny us) His guidance.
Please do write to us if you would like any further clarification on this.
