I was on the Moselle in early October 2022. The weather was mostly cold and wet. I was on a cycling trip, and found I was wearing all of my layers every day. (A cycling top, a fleece, a light rain jacket, and I bought a thin hat to go under my helmet in Cochem.) It was cold early in the morning and warmed up a bit during the day. November would probably be colder, and the days would be even shorter.
Personally, I would never do a river cruise in early November. You are too early for Christmas markets, and standing around while a tour guide does their thing would be quite cold. That said, others do it and enjoy it.