I have a custom domain **example.com** I use for email with Google Workspace.
My Apple ID is also on that domain.

I want to move example.com to iCloud+ but have seen mentions this is hard or impossible *when the Apple ID that purchased iCloud+* is already on the custom domain. E.g. my Apple ID is user@example.com.

Before I start I would like to be sure the migration is likely to succeed.

Has anyone moved a custom domain to iCloud+ that they were already using as the domain for their Apple ID, successfully? Any pitfalls or tips?