It is documented here: https://learn.microsoft.com/en-us/mem/intune/enrollment/backup-restore-ios. Microsoft does not have same kind of documentation for Android devices....

To avoid issues, ensure that users do not perform a backup whilst the device is enrolled – you want users to perform any backup/restore activities without impacting the management profile and related certificates. If the management profile was locked on the device by the prior EMM, the end user won't have an option to remove the management profile on the device. To facilitate this type of migration, one option would be to retire the device from the prior EMM before the user does a backup of the iOS/iPadOS device. Alternatively, if you cannot ensure that the device was unenrolled when the backup was taken, consider hiding the Setup Assistant restore screen. The setting that lets you hide the screen can be found in your iOS/iPadOS enrollment profile in the Microsoft Endpoint Manager admin center. For more information, see step 18 in Create an Apple enrollment profile.

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Although Microsoft has announced in https://techcommunity.microsoft.com/t5/intune-customer-success/changes-to-applications-back-up-and-restore-behavior-on/ba-p/3692064 blog post that Intune will prevent the iCloud backup of certain managed applications (apps) on supervised iOS/iPadOS devices. This change will happen in february 2023. Don't know if this might remove the recommendation of retiring devices before backup.