Did google do something different with these accounts? I didn’t even think they offered a registrar service when they stopped letting you register free custom domain gmails accounts.
My example is Google Play Music, which they migrated to Youtube Music. They probably offered to merge accounts at the time, I don't remember, but I ended up with two Youtube accounts with different playlists that I couldn't merge or transfer data easily. I had to do an annoying dance to recreate my playlists from one account in the other.
The problem is Google Docs which you have shared with many people, Google Photos which has zero rated all my Pixel uploads and will become crazy expensive if manually migrated to a new account. My YouTube channels are tied to this account and a couple of Android Apps.
Calendar is maybe slightly difficult to move. But Email contacts and calendar aren't the problem. In general the problem isn't actually the "Workspace Core Services" that have the lock in. Somewhat funny because they are the ones going away. It is all of the other services attached to the Google account that don't have a migration path like Webmaster and Postmaster tools and Play purchases.
