@dingemansemark Regarding MS: I use Thunderbird with the Owl plugin [1]. Costs a small yearly fee, but allows me to have mails, calendar and a team integration in Thunderbird for several different university accounts. Makes that part a bit easier.

The rclone command line tool [2] theoretically would work great for dealing with OneDrive, to sync locally, but my uni blocks access through that tool. Worth a try tho.

[1] https://www.beonex.com/owl/
[2] https://rclone.org/