The obsidian‑astro‑submodule gist basically uses git to mirror a folder from your vault into an Astro project's content folder.
On Windows 11 with Obsidian 1.5.9 and Node 20 I've had better luck keeping a published folder in my vault, symlinking it into src/content of my Astro site, then running astro dev to preview new posts, so a quick test could be to create a scratch note called TestPost, symlink its folder into your project, run git add && astro build and see whether that gives you a working page; does that fit your tooling or do you need a plugin?
I've tried symlinks before and wrote a whole post on how to do that as well ( https://bryanhogan.com/blog/astro-obsidian ), but I found the GitHub submodule approach better in every way.
[0] https://github.com/No-Instructions/relay-git-sync
[1] https://relay.md
According to the Obsidian roadmap real-time collaboration will be added soon as a core feature.
For anyone interested in making their Obsidian vault into a site there are multiple options:
1. Using the official Obsidian Publish.
2. Using Quartz (or Obsidian Digital Garden)
3. Astro (custom coded, or any other static site generator, e.g. Jekyll or Hugo.
4. Astro Starlight (or any other pre-built documentation tool that can use markdown or mdx)