navigation

Hi all, I'm looking to buy a watch instead of a normal GPS unit that it can handle route navigation. What I want is to load a .gpx file and then into the watch just display an arrow with the direction, meters to turn etc. Something like the Kommot is doing on smartphones but in a watch...

Never ridden using any sort of mapping before, but finding the e-bike is enabling me to explore far more than previously - whats the best app with maps/routes to follow?