What features are you imagining that Forgejo doesn't already have? It's already self-hostable.
The biggest issue IMO is having to create a new account for each instance you want to contribute on, but I don't think that's a big deal (I like having separate identities for privacy anyway)
I suppose some people might also want to open pull requests to merge from one instance to another.
Regarding this Lobsters comment:
🤮