iPhone X Activity and Health app: Doesn't work - shows spinning wheel instead
It really sounds to me like a connection issue, especially since we've established multiple apps being unable to read data from the Watch.

I would go through the process of unpairing and then restoring your Apple Watch to see if that resolves the issue. See: How to unpair and restore the Apple Watch.

If that fails you can call Apple Support as they can actually run diagnostics on your Apple Watch remotely (you will need to have your iPhone with you as well in order for them to do this). It doesn't take long to do and will help identify if there are any hardware issues.