Ive just completed a trip from Naples via Dunkirk to Newton Abbot. 2500km. Very cold in the first 2 weeks! Camping.
I decided to use a mobile phone for nav and bought one with a massive battery, waterproof and loud loudspeaker. Nomu s10. I had OSMAND and Naviki navigation apps. As we were not quite sure where we wanted to go, we did not pre plan a gpx for the whole route but used the apps and c.t do route us in sections.
OSMAND native routing is fairly useless as it cant calculate long routes and it contstantly tries to use the tiniest paths. Naviki was good in "Racing bike" mode but has a horrible map. I tested Komoot extensively but rebel at being "forced" to do social media and it also presented some crazy routing.
In the end the best solution was to let Cycle.travel decide the route (generally "paved"), download, and let OSMAND render it using voice turn by turn. Voice turn by turn uses and keeping screen off uses less battery (and I couldnt find a satisfactory way of mounting a device on my recumbent handlebars anyway). I had the phone in a front pocket.
C.T gives the best routes and we eventually totally trusted it. Also the web interface is easy to use on a mobile.
Many thanks indeed. Ive tried all the apps and websites and they all have deal breakers. C.T + OSMAND works best for me.