OneDrive for Business Plan 2 Sync vs Location limits

Mike789r  The limits are set out here: https://support.microsoft.com/en-au/office/restrictions-and-limitations-in-onedrive-and-sharepoint-64883a5d-228e-48f5-b3d2-eb39e07630fa

Read the section "Number of items that can be synced or copied". Even though they have limits in the hundreds of thousands I would stress that these are limits that may work when all parts of the system (individual devices, network, tenant) are operating at optimal levels.

For this quantity of files I would not be using OneDrive syncing but storing items in SharePoint with selective syncing of folders. Mass syncing across users/devices creates multiple points of failure and you will spend nights crying yourself to sleep dealing with users who have deleted or corrupted massive folders, or whose devices have come to a crawl trying to sync, or whose current documents are not updated because they're at the end of a 10,000 file sync queue.

If this is a lift and shift of a file server, then it's not a good approach.