The "New Outlook" demands that when adding your Gmail account, you also give Microsoft a copy of all your email, contacts, and calendar data.
The "Learn More" link confirms:
"Syncing your account to the Microsoft Cloud means that a copy of your email, calendar, and contacts will be synchronized between your email provider and Microsoft data centers."
We really should consider services that are not #ActivityPub based but still a federated to be part of the #Fediverse and promote them accordingly. Self-hosting is a plus.
#Usenet is also federated and has been since 1979! There are free providers: https://www.big-8.org/wiki/News_service_providers. If one excludes binaries groups, it's possible to peer with other providers via #NNTP. Posts and groups are linkable in HTML.