Tools from Synology NAS to allow exporting data out of the Microsoft 365 cloud

Synology CloudSync

You will need the login details of the user to export their OneDrive and Sharepoint Sites, copy that Synced CloudSync data to an USB or external drive and hand to the user.

Active Backup for Microsoft 365

You can backup the tenant or just the user.

Using the Active Backup for Microsoft 365 Portal you can export the entire Mailbox to PST, but the exported PST only contains Email, No Contacts, No Calendar entries

Calendar Entries and Contacts can be exported but they seem to only be able to exported in batches of 100 at a time. This is highly annoying if you have thousands of contacts or calendar entries.

A work-a-round for Contacts is to export them to CSV using the Outlook Web Client and then import them to your destination