One Business AppleID for all Devices, with Employees

I've never seen this in operation but it may be what you could use for your collection of business devices:

Use Managed Apple IDs in Apple Business Essentials

A user can have two types of Apple IDs: a Managed Apple ID and a personal Apple ID:

• A Managed Apple ID is provided by your organization, and users that are assigned to an Apple Business Essentials employee plan can use it to sign in when enrolling a device into device management. It also provides access to iCloud for collaboration and backup. Apple Business Essentials makes it easy for organizations to create and manage these accounts at scale.

• A personal Apple ID is used to access personal data such as Photos, iMessages, and other personal iCloud data when signed in to a personal device.

There is more reading in the Apple Business Essentials User Guide

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