I see that no-one has mentioned
https://cycle.travel/
Not an app, but a website.
I've plotted routes of well over 1000 km on it.
Functionality for accommodation is optimal in Europe, but I found its routes superior (and safer!) to Komoot in the U.S. although it's address search function was weaker (or perhaps that was my lack of experience witn US addresses).
Instant access to Google Street view is very handy in tbe planning stages.
Definitely worth investigating.