As a matter of Principle:
On Fridays, it has been made incumbent upon Muslims to pray in congregation at the time of zuhr prayer and in place of it. As soon as the Adhan is said, it is incumbent upon all Muslim men to leave all their involvements and come to the mosque if they have no legitimate excuse. But since the rulers are no longer fulfilling their religious duty of conducting Juma congregation, and it is only the religious scholars who consider a duty to keep the practice alive no matter in a distorted way, we cannot declare that attending the Friday congregation is the obligation of the same status. If someone cannot attend the congregation he cannot be declared non-Muslim not to say of non-believer. This is because the necessary elements of the Friday congregations are no more there in the practice.
As for your Question:
You can Pray Nafal Salah during Khutba, but it is advised to keep it short.
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Discussion 30993