More information in this Open Letter and the status updates to it:
https://gitea-open-letter.coding.social/
Things boil down to the incorporation of Gitea Ltd and transfer of domains and trademarks to that business entity, without consulting the community. Wwith that Gitea is effectively no longer a community-driven project.
Forgejo is only a soft fork under custody of Codeberg who will use this as their downstream.
Forgejo is not yet launched, and the project wants minimal disruption / drama.