I have a work around that is working for us.
The email for the Team Group is the culprit. I get the emails, because I belong to the Z_Test Group.
Whenever a Teams calendar event occurs, an email is sent to the entire group by default. I haven't worked out how to disable this. I suspect, if we disable that, it would break something else.
My Sharepoint Site, Group and Team is called Z_Test. When I created the Team Sharepoint Site, the default email address is z_test@mydomain.
I DON'T want emails sent to: z_test@mydomain & notme@mydomain
I DO want emails sent to: z_test@mydomain & me@mydomain
We can exclude the DON'T want emails using an Outlook Rule. (Outlook Settings / View All Outlook Settings / Rules / Add New Rule
--> If you don't add the second condition, you will miss out on emails you do want.

Optionally Move To | Deleted
A very small annoyance for each user to setup, but we can then use Team Calendars, and Channels as intended, without the unwanted emails.
Any of the Channels I'm not part of, I can hide them and disable their notifications in the channel settings.