The issue with Microsoft OneDrive, not showing on the Menu bar, is a issue with the Menu bar having too many icons to show and so icons that overflow the Menu bar appear to be missing and there doesn't seem to be a way to expand or organize them.
To fix this issue and see the OneDrive icon again, go to [System Settings>Control Center] and from here...
- Change the "Show in Menu Bar" items to "Don't Show in Menu Bar"
- Look for "Green" sliders that say "Show in Menu Bar" and disable them so the slider is "Gray"
This will clear out all the system icons taking up space in the Menu bar leaving the only items in the Menu bar area from 3rd party applications like OneDrive.
Now you can right-click on the OneDrive icon in the Menu bar as normal and adjust it's Preferences.
Finally it's safe to start enabling system icons again by changing them back to "Show in Menu Bar" but do this one at a time until you see the OneDrive icon disappear, this will let you know how many of them can be on without hiding the OneDrive icon again.