Forgejo (Gitea fork) has been working for multiple years to add support for this. It will still take a lot of effort to finish, I doubt we will see anything usable this year.

Originally the plan was to PR the federation support to Gitea as well. I'm not sure if this is still the case, considering the rising tensions between the two projects and the fact that Forgejo is now a hard fork.

Forgejo, a Gitea fork that I use, has support for it according to the page you linked. But the FAQ for Forgejo mentions it's on the roadmap so not sure how complete ActivityPub support is in Forgejo either.

https://forgejo.org/faq/#is-there-a-roadmap-for-forgejo

I only use my Forgejo instance for myself currently so I haven't looked at the ActivityPub features of it before.