Hi @JustinMicheal-7973
Where are your users located now? For the quarantined users in Exchange, we could refer to the method introduced in this link to remove them:
Removing Old Quarantined ActiveSync Devices from Exchange Server
And if you want to allow them, Office 365 - Allow a User's Mobile Device using PowerShell
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
In addition, here are the official documents introduce about
Using hybrid Modern Authentication with Outlook for iOS and Android
Account setup with modern authentication in Exchange Online
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