Microsoft suite (Teams, Planner, Outlook etc.): Why it's bad and what are the alternatives? (also Teams for education?)

Hey, everyone. I was wondering if you've got references on why **not** to use the Microsoft Suite for managing businesses (internal communications, work collaboration, emails etc.) and what available alternatives - more private and secure - are out there. Also, is using Teams for education (remote classes, hand-outs, documents etc.) a good idea? Why (not)?

I searched for it but many results were microsoft propaganda lol (or recent infosec vulnerabilities of Teams) so I'm asking you :)

bad education etc microsoft outlook privacy teams