I refuse to believe that Garmin Connect still does not work as intended with Apple Health as it should.
Apple Health and HealthKit were released in 2014 and even being very patient one can only wonder about the lack of interest and competence from the developers at Garmin to get things working properly.
The forums are full of problems, just search for "apple health" and / or "HealthKit" - so in won't start another thread listing all bugs.
No support for Apple Health at all would have been better that the broken system that Garmin implemented in its Connect App
Who else is very disappointed / annoyed by Garmin's complete lack of interest, competence and communication concerning this matter?