Outlook, Outlook Calendar, Teams, SharePoint... I'm honestly baffled by how bad they are. It's like it was made by aliens who only sort of understand what human beings want. And, of course, Microsoft is super selective about their product managers and pays them a ton of money--even though a golden retriever could have come up with a better UX. Literally all they had to do was fucking copy Google.
The version of outlook I have to use for work is beyond terrible. There is no way to filter calendar appointments into a separate inbox and it doesn't let you easily set emails as unread. It's a fucking mess. There is random dogshit buttons everywhere.