This has bothered me for a while now and whilst FR11.21 now fully supports Modern Authentication, only OneDrive does not require an App Password. To generate an App Password, Microsoft Azure AD "Security Defaults" must be disabled and that requires a Azure AD Premium P1/P2 license for every user in Azure. Customers with "Security Defaults" enable either have to pay extra to be able to have any Exchange Online/SharePoint Online backup capability. The discussions I have had with Commvault is that Exchange Online/SharePoint Online only have limited Microsoft Graph functionality that affects some admin calculations as well as some Backup/Restore functionality.
In a future feature release, can Commvault and especially Metallic have an option for limited protection of O365 environments using just Graph alone? I understand that it won't be perfect, but perfection is often the enemy of progress and I have observed that others in the market have adapted to Microsoft's paradigm shift.