Any reason to fork it instead of just contributing?

Here is a list of forks on codeberg, unfortunately none of them has more commits than the original repo.
Of course it is possible someone put the project on GitLab or GitHub or somewhere else.

My recommendation is to move on. Sooner or later Eternity won’t be able to keep up with lemmy developments or even break. Better get used to another app before that happens. I can absolutely recommend Voyager for Lemmy, give it a try.

I guess someone will post here as soon as they are willing to develop Eternity any further, but there is no point in waiting.