Gitlab is also thinking of going to federation. It will be interesting as git is already a federated protocol, now our prs, follows, stars, ect will also be federated between different instances.
I recently looked this up again and it looks like the person who started the federation work in Gitlab got a new job and isn't really working on it any more. So sadly this seems to be on hold as Gitlab the company is not themselves investing staff-hours into federation.
That is too bad, but also at the same time I kind of lost hope for Gitlab after they jumped on the AI hype train, if they're going full corporate they probably wouldn't be a good candidate for Federation (both because other people would defederate them and because they wouldn't want to because competition).
I've read in some issue tracker that the gitbal guys aren't really interested in federation. It makes sense, they are a business. Seems that having push mirrors is a premium feature, so federation would go contrary.