This is rolling out now. ”Sensitivity labels enable admins to protect and regulate access to sensitive organization content. We now support sensitivity labels when creating teams with templates.” https://www.microsoft.com/en-us/microsoft-365/roadmap?filters=&searchterms=84232

I create a provisioning process with Forms and PowerShell to create a Teams from a Template and add a Sensitivity Label the Use choose. https://github.com/MicrosoftDocs/microsoft-365-docs/blob/public/microsoft-365/compliance/sensitivity-labels-teams-groups-sites.md It´s also possible to list all Teams and add a default label on all Teams. Template idea: Today you choose a Label and can create a team from scratch. You want to add the Template, too. For example you choose a label like "Internal" and the template (Manage a project) will be created with the Label and the policies work, so that no external has Access and it´s a private team. Thats a good idea!

Thanks for the feedback Frédérique!