A small note: what's the difference between GitLab, GitHub etc? Are they companies with a substantially identical target: making money? Does they offer storage on their own server (or even worse others servers in a chain)?
So why the hell instead of moving from a company to another ANY FOSS dev do not came back to classic ML (mirrored offline in personal maildir) and use hosting, multiple if possible, only as a mean to offer a shared repo? Why not even serve the project via the repo itself like fossil?
There is a world outside the web, on our desktops.
Just as a suggestion: try to disconnect your desktop and look what you can or can't do. If you feel "empty" you are in danger.
The reason people put their code online is because it is a convenient way to host it, and often platforms like these have some ancillary tools that make the code easy to work with.