The Garmin connect synchronization to Apple health still does not work well.
1) you have to leave the app open due to Apple’s restrictions on how apps are allowed to write to the encrypted health data, but there is no notification when the activity gets synced to Health. A simple popup would be pretty helpful.
2) when the connect syncs activities it appears to grab about the last 2 weeks and sends them to health, overwriting the previous activities. This wipes out any metadata added via health, like the effort rating for tracking RPE load. A simple check to see if there’s a matched activity would work a lot better, and probably help shorten the mysterious “how long do I have to leave the app in the foreground” time delay.