Excellent point, Tim. My old phone died. Would not boot at all. When I registered the Microsoft Authenticator on the new phone, some glitch prevented it from doing MFA. It took two weeks working with Microsoft to gain access to my (personal) Azure Portal and M365 account.
We should have at least one backup MFA method. I like using FIDO keys since they don’t depend on the phone and I can register more than one. You could do email but that’s not as secure and if it uses MFA…