The fact that Garmin only seems to want to write data to Apple Health it is extremely frustrating that it will not read data like weight, body fat, hydration etc. Given that Apple make an API for the app developer to make a call for that info does part of the work for Garmin.
Also the lack of all metrics bee written to Apple Health like HRV is another frustration.
I can understand Garmin would like us all to only live in a Garmin ecosphere but reality is we don't for various reasons and at the end of the day the only damage is to Garmin. Having been a Garmin bike computer user going back the the Geko 301 and currently an Edge 530, I very nearly went to Wahoo at that point. This stubbiness to embrace your consumers multiple requests for better integration doesn't help your brand image.
We need to have better integration between Garmin Connect and Apple Health.