Yes, our maps are GPX, FIT or TCX file agnostic (means they don’t care, as that feature/function is a system/firmware level one, not a map specific feature/function).
You can use any GPX, FIT or TCX file from any other source on my maps (as long as the Garmin device supports that specific file format).
So GPX or other supported file types from Komoot, ViewRanger, OutdoorActive, Plotaroute, Ordnance Survey (OS), AllTrails, Walking Highlands, or any other third party app or website that offers such files will work.
If you don’t know what the difference is between Route and Track files, you will find the answer here.
If you don’t know how to copy a GPX file to your Garmin device, you will find the answer here.
If you have a Fenix/Epix or similar Garmin smartwatch and want to know how to get the GPX files from another site/app on to your watch via Garmin Connect, then Garmin have a page on it here: https://support.garmin.com/en-GB/?faq=wKuZXCaZRP4mWPX5aRz5h5