I have two issues related to Apple Watch development.
1. Cannot pairing Apple Watch with iPhone.
I cannot see my Apple Watch pariing with iPhone in the Device menu of Xcode. It shows "null" value of paired Apple Watch.
But actually Apple Watch is working well with iPhone.
2. Automatic Code Signing issue
I developed watchos independent app based on watchos 6 and then I tried to do Automatic Code Signing.
By the way Xcode doesn't create an app id in the developer portal.
Pleaes let me know if someone can help me.
To your second point, I struggled with this too. I had to create my own app id and set up the Health and Sign-In permissions.
In addition to that, I had to create and link an additional plist file for the health permissions. There, fortunately, is a blog post on this here: https://learningswift.brightdigit.com/independent-watch-app-healthkit-permissions/ I mention this because you may well hit that next.
The process of submitting Independent Apps to testflight has been pretty rough.