You can do this using Forge within Magit already! And it also works for Gitlab: https://magit.vc/manual/forge/
The only package I've been ultimately responsible for is the Gruvbox theme[^1], but that was very quickly handed over to other emacsers :)
I still find it a joy to write and it's one of my more preferred rabbit holes to dive into. Maybe one day there'll be something more to share :)