Adding custom Options to a Select must be done in Source/YAML

I was having an issue with a Province/State field in a Basic Address element. I could choose between the "State/Province Codes" option and the "State/Province names" option. But since those only have US states, and I wanted to include/prioritize Canadian provinces, I created a new Options list, as suggested.

However, this was not being added to the available Options for selecting in the Webform UI for that field in the Basic Address element. And I could find no way to tell the field, "hey, there's a new Option group available to choose". Only the two default options were allowed to be chosen from.

Searching led me to https://www.drupal.org/project/webform/issues/2937109, which gave me the clue I needed to make it work. I could just paste the machine name of my new Option group into the Source/YAML of my form.

That works fine, but it seems like a big workaround, and there's an additional problem: if I re-visit the field through the UI and don't make any changes, it's fine. But if I make a change to something in the UI, it throws an error upon Save because the "State/Province" field select list isn't actually pointing at anything. So after I make any change in the UI, I have to choose one of the default options, then go back into the Source and re-input the proper Option machine name.

Once saved properly, the Options config page properly reports that it's being used by this webform.

I'm reporting this as a bug, even though jrockowitz indicates in the above-linked thread that you'd prefer not to create a UI for this type of thing. I get that desire, but then it seems the usability is severely limited, since it's not at all intuitive that an admin can't simply create a new Option group and then have it available for any given select field. And, further to that, there's then a mismatch between the UI and the YAML, which leads to the "Select is required" error when making any change to the field through the UI.