Do you want to display your Outlook Calendar entries in a third-party Calendar app? Then I think you need to install the native Outlook app from Play Store or wherever.
If you don't need that, you could use the (progressive) web app for Outlook. That's what I do, and the additional sandboxing in Vanadium keeps it nice and separate from the rest of my user profile. That way Microsoft can't communicate with other apps in my user profile.