I know the pain of cliffhangers, I had a couple of series back in the day that ended on a cliffhanger and didn't get renewed, and that sucked so bad.

One good thing about Good Omens is that Neil Gaimain has come out and said that he will not leave the story unfinished, if the worst happens he will write a book if need be. Either way it will be a long wait, he's said if the writers and actors strike finishes soon the soonest that they could get started filming would be 2024, and the soonest they could expect it to premiere would be 2026, because supposedly these productions require quite a bit of post production to make.