Reitti’s author also posted here some days ago.
Reitti does not have a dedicated app and is fed with GPSlogger, which is capable of feeding dawarich as well (or both at the same time), actually more reliably than the dawarich app in my experience (dawarich just stopped working after a couple of days and needed a full logout/login).
Edit: Colota mentioned ITT does the same.
Actually Dawarich and Colota are both in F-droid.