Rhi @benni thnaks for your question, I will get back to you with this soon
RHi @benni can you please check/share docker logs?. Based on what I understood, I strongly feel like there's an issue on Peertube's side and the way it handles permissions.
RHi @benni it should be able to do cross org logins, it depends on how you have your project settings for the project on which you were trying to login
Ryou can read about it here more https://zitadel.com/docs/guides/manage/console/projects#grant-a-project and let me know if that helps 