That's still a SPOF though. Over the years I've had various letters from registrars and registries threatening my account due to missing information or new requirements.

GANDI themselves once accused me of ToS violation because one account uses my initials ( as on my bank account ) instead of my forenames that they demanded. I migrated everything out of that account ASAP.

Ideally you need two completely different domains ( to avoid potential trademark issues ) in two different TLDs at two registrars.