Allah's Sunnah

S 33:38 There was no difficulty upon the prophet in what Allah had made obligatory for him. Allah’s sunnah concerning those who had passed away before. And Allah’s command was predestined predestination.

S 33:62 Allah’s sunnah concerning those who passed away before. And you will not find a change to Allah’s sunnah.

S 48:23 Allah’s sunnah which had passed away before and you will not find change to Allah’s sunnah.

Allah's sunnah had passed away but there is no change to it? Compare with S 15:13

They do not believe in it and the sunnah of the first ones has passed away.

So defunct.

But: S 18:55 And nothing prevented people from believing when the guidance came to them and asking for forgiveness of their lord except that the sunnah of the first ones comes to them or the torture comes to them in various kinds.

So was it still about?

In S 17:77 we read: Sunnah of him we sent before you of our messengers. And you do not find conversion for our sunnah.

The unnamed messenger's sunnah was also that of Allah? Or were there two?