Thank you for your feedback. We’re happy to announce that Mac support for sharing system audio is now available to users who have opted into Public Preview.
You can learn more about the new Microsoft Teams Public Preview program here: https://aka.ms/TeamsPublicPreview, and Teams administrators can find documentation to manage which users will see the Public Preview option here: https://aka.ms/TeamsPublicPreviewAdmin
This feature is on the backlog. We’ll update when we have more details to share.
The Calendar team is working thru plans for Meeting Delegation.