I first came across the book in 2017, bought it and was immediately hooked by the story.
Years passed, and when they announced the casts for the series, I was skeptical (I'm not a big movie/TV person) as I knew nothing about Michael Sheen and David Tennant.
Decided to give it a try, and boy, it's so good. Everyone is so perfectly casted.
While it was never written, Terry Pratchett and Neil Gailman talked about the second book all through the night whenever they shared hotel room while promoting the first book. It's somewhere on Neil's tumblr where he said that.
So while it is only Neil that wrote the second season, i think he'd know what Terry wanted out of it too.