I will share my experience, we removed federation.
When ABM federation is in progress there is no way to stop it.
Resolve email conflicts.
After 60 days - when conflicts are resolved you can complete ABM federation or just disconnect it(this was my case).
Call Apple support, and they can check from their side when changes are propagated.
Remove your domain from ABM.
All existing accounts(admin accounts) will be automatically transferred to "yourDomain.appleid.com" and you can log in to ABM with that account.
After that Add your domain again in ABM and verify it.
After verification your admin accounts will be able to log in again with "@yourDomain".
Apple IDs can be created with "@yourDomain" again.