There should be a way to boot someone out of the system. We would like to be able to log people out of the system (for example if the system is going through a major change and would like agents to make no changes). We can remove them from the M365 Agent group, but this appears to still let them log in if they are still logged into the system. It only comes up with an error if they were logged off and try to re-authenticate.
Adding a Session Time-out does not work either - as for some reason this does not boot everyone out either. So the ability to bulk boot people out of the system so they have to re-authenticate would be much easier but it does not appear this feature exists.

