The Konosuba light novels are known for their comical and unique storylines. Usually, in each novel, Kazuma and his party face new challenges in the fantasy world. In the latest one, I assume they might be encountering more powerful foes or getting into some hilarious misadventures. But without reading it, this is just speculation.
The Konosuba light novel is not a fanfic. It has its own unique plot, characters, and world-building developed by the author's imagination and creativity.
The Konosuba light novel is good. It has a charming mix of fantasy elements and comedic situations that make it highly enjoyable. The character development is also well done.