Current working strategy is to first move everything using Entra SSO to our own hosted IdP, and then everything else. From there we’re thinking we move SharePoint/OneDrive, and replace the Office apps with LibreOffice (maybe Collabora?), and eventually replacing email with Fastmail, which we already resell.
We’re a managed hosting firm with a few technologists, and we have no external MS365 collaborators, so we’re a good fit for that kind of setup.