Wahoo fitness emails .gpx files directly to one's log. Maybe the same process would work for you. The mail address you need is data+???+mopruonb@attackpoint.org, where ??? Is your AP user number. Ask Kenny.
Thanks Charlie; I'll look into that solution.
Not sure how much of this you already know. Go to settings, next to your name in the upper right, and then to edit profile/preferences. Toward the bottom is a place to check to enable email of .fit files, and the email address to send them to. They then show up like magic in your log.
Now it's just a matter of finding out how to share activity files from Wahoo fitness (or Garmin connect) on our particular smartphone system.... No success yet.