In my opinion, project hosting is not the most important. But, a network connection for developers, around keywords or ideas are the best. Maybe, a platform to brainstorm, discuss ideas, implementation would be awesome.

Project hosting is maybe reinventing the wheel: GitLab, GitHub, BitBucket, there are too many providers which do this job perfectly.

Let developers do their stuff on those ones. And let them come back to find new contributors / friends.