In general, I’ve been really pleased with my fēnix 6, but Garmin’s unwillingness to properly merge data recorded on other platforms/devices remains a massive annoyance. Fortunately, I’ve figured out a work around; which as stupid as it is that I need to do this, turns out it works pretty well.
The “solution” should have been obvious to me at the time, but blinded as I was by the pink-fog-of-disbelief, it wasn’t. Simply record the activity on the fēnix 6, then discard it. This solves the watch-as-single-source-of-truth and don’t-want-duplicates problems in one completely inelegant package, with a small cost in battery life. Again, I think it’s absolutely ridiculous that I have to do it, but hey, not really the hill I want to die on.