As the Nafl is supposed to be prayed before the Farz prayer, if I want to pray the Farz prayer at the exact time, would it be right to pray the Nafl before the time of the Farz prayer starts?
Bismihi ta'ala
If you pray the nafilah prayer, then that is the mustahab thing to do, to pray it on its time, and then pray the wajib prayer, and with doing this, you will not be deprived of anything.
You will gain the reward of the nafilah prayer, and the reward of praying on time, which in reality that is what you are doing.
Therefore, there is no need for you to pray the nafilah prayer before its allocated time.
And Allah knows best.