Go to the team name, and select More options More options button > Manage team.
Select Settings > Guest permissions. Check or uncheck the permissions you want to allow.

Explanation:
Only global admins can create org-wide teams and currently an org-wide team is limited to organizations with no more than 10,000 users. There's also a limit of five org-wide teams per tenant. If these requirements are met, global admins will see Org-wide as an option when they select to build a team From scratch when creating a team.
https://learn.microsoft.com/en-us/microsoftteams/create-an-org-wide-team

To identify whether Teams calls are using TCP or UDP in the Microsoft Call Quality Dashboard, you should review the Quality of Experience Reports (option D). These reports provide detailed information on the quality of voice and video calls, including the network route used, packet loss, delay, and other metrics that can affect call quality. In these reports, you can identify whether calls are using UDP or TCP.
https://learn.microsoft.com/en-us/MicrosoftTeams/quality-of-experience-review-guide

An administrator will have to enable the expiration policy and set the properties for it to take effect. To enable it, go to Azure Active Directory > Groups > Expiration.
https://docs.microsoft.com/en-US/microsoftteams/network-planner