Forgejo contains all of Gitea, and that has the benefit of allowing Forgejo to be a drop-in replacement. With the decision to become a hard fork, this will no longer be guaranteed
I'm glad to see them move their own direction but I'm skeptical considering the amount of commits they take directly from Gitea. I could see this becoming more like a Fedora/Rhel type of fork but we'll see.
I'm personally staying with Gitea for now as I have yet to find a reason to switch.