I have taken "workgroups" to the cloud.
We're in the midst of planning migrations this year for some clients with on-prem servers. Notably...for quite a few clients with SBS which will hit EOS next Jan.
Going through some training for Teams, Sharepoint, Pilot, yeah the larger the client..esp with heavier on-prem stuff...the more complex this is.
For smaller clients with basic needs...it's easy. For clients with complex networks and heavier file usage...we're struggling.
A hard part is getting rid of 30+ years of "Mapped drives to the server" habits...at least if you're putting people up on O365 sharepoint/teams.
We need to get training on Microsoft 365 (not O365)....and "EMS"..and more Azure services to replicate some form of control via Azures directory.
For many clients we'll likely still maintain an on-prem server. Setup dirsync. Some clients have apps that need to live locally...on -prem. But at least we move their email to O365, and file storage to SP/Teams.
We may have some clients were SP/Teams may simply not work for them...due to complex file storage, or..they just don't have the time to re-organize their folder structure so that it can work in SP/Teams. Because...for a client with decades of bloated folder structure on the "shared drive"..ya know, folders within folders within folders within folders within folders (repeat a dozen more times)...that will_not_work with SP/Teams.
So when migrating to SP/Teams...you need to wipe the slate clean and spend a lot of time with the client to replicate a secure storage setup, permissions at the top level of sites/teams.
We do welcome suggestion from peeps here who have experience with other cloud file/storage services that allow mapped drives in a more conventional manner, with deep folder structure allowed...for those old legacy pain in the butt clients that HAVE to have things work like the old days.