Like other commenter referenced, the markdown-oxide LSP replicates the core of obsidian better than obsidian does. I use it with helix. I described by setup in more detail above: https://news.ycombinator.com/item?id=48180639

I use vimwiki. I know vim and appreciate not having to learn a new thing. The output is just markdown files linking to each other, so it's very portable.

Maybe leaf : https://github.com/RivoLink/leaf

nvim + markdown oxide is the closest I've found https://github.com/Feel-ix-343/markdown-oxide