Update. For some reason it does now present the “Instances” and “Enter server manually”
If I enter the local url: http://10.0.0.199:8123/ it tells me to continue on the phone, where it spawns a browser to login to my HA which works. It then asks if I want to allow the watch to stay signed in and I say “ALLOW”.
Then nothing happens. Once a little cloud popped up, too fast to read, but I think it was a Could not connect. Then it just forgets everything and goes back to blank.
It should be obvious to anyone, but asking for a full protocol HTTP url on a watch screen is akin to “User torture”. Things like :// is a pin to find and use. So I’m less keen to try it again now.