Assigning a domain to a Preview environment on any branch?

I want to assign a custom domain to a Preview environment for any branch (not just a particular branch). But it looks like I can only assign the domain if I specify a specific branch:

Can you confirm that my understanding is correct and, if yes, whether you plan to make it possible to allow any branch?

The domain troubleshooting guide can help with most custom domain configuration issues. You might be able to use that guide to solve it before a human is available to help you. Then you can come back here and share the answer for bonus points.

You can also use v0 to narrow down the possibilities.

What is the result you are looking for here? Do you want any deployment to any branch to override the deployment at custom-domain.com?

Yes

I want to point docs-staging.sablier.com to the Preview environment deployment, regardless of what branch it was triggered from

vercel alias can help with that

Automatic domain assignment is tied to specific branches, but they can be aliased manually or automated with GitHub Actions

Thanks for the info. It would be helpful if there was a way to do this without manual GitHub Actions setups.