Hello! My name is Mostafa, and I will try my best to assist you with this so that you find a satisfactory solution.
I’m sorry that you are experiencing this issue. Microsoft Teams does not provide a specific feature to disable team owners from changing a private team to a public team.
Set up notifications to be sent to a Global Admin when specific actions are taken in Microsoft Teams. This can be achieved through the use of Microsoft 365 auditing and monitoring features.
- Sign in to the Microsoft 365 admin center with your Global Admin account.
- Navigate to the Security & Compliance center (https://protection.office.com).
- Go to the "Alert policies" or "Alerts" section, depending on the layout of the Security & Compliance center.
- Create a new alert policy or modify an existing one.
- Configure the alert policy to include the specific activities you want to monitor, such as "Update team settings."
- Specify the recipient(s) for the alert: the Global Admin or a group of admins who should be notified.
- Save the alert policy.
If the above steps do not help, reach out to me, and I will be happy to help and try my best to resolve your issue. Thank you.
Best,
Mostafa