If I have absolutely nothing prepared, like I don’t even know anything about the world or the situation the players are in, then I reschedule session 1 ;)

You almost never have nothing prepared. If I didn’t prepare for a session, it just means whatever was there gets built upon in a more rudimentary way, areas have less detail, characters are more rough, no nice maps, but otherwise everything is exactly the same. The stuff you do in preparation just means that the session will be better. If you don’t prepare, you’ll essentially just do “preparation” on the fly and it’s called improvisation. You don’t do drafts and discard them for something better, you just always go for the first thing that comes to mind.

So idk, for me, not preparing for a session is pretty simple, I just do everything the same just in less time.