You can make it such that nobody, except those with the Administer Jira permission, can create new team-managed projects.
Removing this permission does not delete existing team-managed projects. Users with the Administer Jira permission can always create team-managed projects, even if that group is removed from this permission. (If you'd like to prevent even admins themselves from creating new team-managed projects, please vote for https://jira.atlassian.com/browse/JSWCLOUD-21477 as suggested by @Vero Rivas
You can remove this permissions via the Global Permissions settings in the System settings (you will need to be a site admin or a Jira admin to do this). Here's some screenshots to guide you :)
Thanks, just what I needed to stop some of the annoyance with users creating Team managed project and then realising the limitations after. Then requesting a new company managed, leaving the team managed and then I can find and clean up or start all the migration work. Waste of time this functionality.
Team Managed Projects have been a huge frustration for me as an Admin. Users being allowed to create them, and then "hide" them from Admins if they are not added as a Users on the project (we have 3 legacy Team Projects in use our and our Team Projects cannot be "public" due to and the fact that we have external Users with specific permissions to allocated Projects ) is very counter productive. I have taken away all permissions, but Users can STILL create Team Managed Projects! Does anyone else have this trouble? I may need to start a new ticket :/