I think it would be interesting and also that you would get support letters to support your grant application. In addition to the link @onepict provided (very boring read but totally worth it), I’d like to add that GitLab is very unlikely to merge a patch for federation, because it goes against their commercial interest. For instance the git mirroring is only implemented one way, mirroring both ways is a proprietary feature. If you need more clues, there is a collection of issues related to federation that did not make progress over the years in this topic.
In your grant application, I suggest you plan to send a merge request with federation features to Heptapod.net instead, which is a GitLab fork maintained by @gracinet. And he recently said he would be happy to review such a merge request.