The JJBA manga is indeed finished. It had a great journey and wrapped up with a satisfying conclusion for fans. However, there's always the possibility of spin-offs or related works in the future.
It could show their friendship developing or present a challenge they face together. Maybe it gives us insights into their personalities and how they interact.
One of the descendants could be Giorno. Giorno has his Golden Experience Stand and is quite different from Jonathan in many ways. He's part of the new generation of the Joestar family. Also, Josuke could be among those he meets. Josuke is known for his Crazy Diamond Stand and his strong sense of justice, which he may have inherited in part from Jonathan.
I recommend the following three novels to you:
1. [Return of Death: The protagonist is a young policeman. After experiencing the apocalypse, he has to face the test of life and death.]
2. The protagonist was imprisoned in a prison that extracted the souls of the dead. This involved the plot of One Piece's world.
3. "Blood Class Rules": The story revolved around a bizarre incident in a school, and the protagonist and his classmates fought to the death. If you like suspense and explore the story behind it, this book is very suitable.
I hope you like my recommendation. Muah ~