NVIDIA's user-space components remain the same and are closed-source, but great to see the NVIDIA open-source kernel driver bits being mature enough to now be preferred over the proprietary ones on supported GPUs.
How is it open source? In the history of the whole repository, there were 11 merged PRs in 2022 (when the project began), and no merged PRs after, even though lots of PRs have been submitted since then. There has never been an issue-fixing PR merged, and no issues or PRs are submitted by the maintainers of the project.
All of their commits are tagged versions, none of which tell you in words what they did or what changed, it's clear that they still do their actual development internally, and the GitHub repository does not contain that incremental work. Because the commits are releases only, there are only 65 commits on the main branch from May 2022 to the latest commit/release 4 days ago.
so NVIDIA,
IMO there's nothing about Arch, or any other distro, that makes it worth using, beyond whatever goals you have. If Arch helps you accomplish that goals, great. If not, pick a different distro that does.
In my case, I want to use the latest version of software and use my own configs without inadvertently breaking stuff, based on some arbitrary set of assumptions that distros like Ubuntu or Fedora have made about how their own distro should be used, and Arch has been the easiest way to do that for me.
Also, as others have said, AUR and PKGBUILDs