@ChristianJBergstrom that's a pain as when you set an event via Teams you can't set time to 'free' (such as when you set up a holiday and want everyone to see it but not block out the calendar). So these have to be set up in Outlook but I can't then invite the Team as such.

@ChristianJBergstrom We are really trying to leverage teams with our local and remote users and have a need to have one place to go for all general information for the team.  We have a channel for this with it's own calendar and it would be extremely useful for users to be able to schedule "meetings" with the channel calendar to show when they will be out-of-office.  So this is a big limitation of channel calendars for us.

I think you can try my way:
background is : team is actually "account"
1, find your team email addr. in azure portal/TAC, it should like teamname "with number(if duplicated)"@onmicrosoft.com
2, change email to visible in exchange(by default every team email addr. is invisible for user in exchange"
3, then you can add its calendar in outlook

I will stop from here as it's too far from what MS wants: use Teams