Mapout is nice because of how simple it works. The map looks pretty good with their custom theme and the map loads and renders fast without getting in the way. That said, Mapout is not really a navigation app, it doesn't do turn by turn navigation, but it will show the route or track and where you are on it.
Importing a GPX file into Mapout
1. In the phones 'Files' app navigate to the GPX file you want to import.
From a MotoTravel download this'll be the file with 'track' in the filename.
2. Long press the file you want to import and press 'Share' or 'Open in' from the popup menu.
3. Tap Mapout from the list of apps.
4. Once completed the app will show the imported track in the tour organizer screen.
5. Tap the back button in the top left to go to the map screen and see the route appear.
Reference; I use an iPhone with iOS 15.