How to set up Projects for multiple departments where each dep only sees their own?

[wiki-admin]

We are an organization with about 2500 Employees. In our department we would like to use the App Projects to keep an overview of our ongoing projects. The big BUT: The projects should only be visible to our department and not all people with app access, as other departments might have or receive access to the app over the course of time too.

How can you do that in a reasonable way? 

Currently you can either allow global access for a project, then everyone with app access sees it. This can't be restricted later on anymore, which is annoying, because if this happens we need to tell our people internally to create the project again as restricted one.

Then, if people manage to create the right project type with permission control, you can give all 50 people view access to the project. But unfortunately you cannot select a team anymore (as still mentioned in the documentation https://support.atlassian.com/platform-experiences/docs/set-up-permissions-for-projects/). So each time an employee leaves or joins the organization you would have to maintain this separately for all e.g. 30 running projects.

Is there a better way to handle this?

Thanks in advance!