I constantly hear this but I just want to be the counter argument here.
Self hosting email is not the impossible tasks that people make it out to be. It is on the more advanced side of things though if you are hosting your primary email that you rely on.
I've been hosting my own email forany years now and have had no issues whatsoever but I also have years of experience and know how email works better than many that have no interest in such.
I would NOT recommended starting your self hosting journey with email but I will never discourage people from doing it.
Take your time. Ask questions any time you don't understand something. Be ready to learn a lot and design a solid plan for disaster recovery.
What's bad about it? I'm a Linux admin by nature but an admin of all by profession and overall I have no real complaints about Teams. Has always worked just fine for me and to my knowledge everyone else.