The conversion is not an issue, there are already multiple tools for that, including a browser plugin with auto refresh.

However the tight integration with the editor, in this case neovim, is missing. At the bare minimum it should show the changed area curently being edited, ideally scroll with the editor scrolling like with common markdown extensions. Currently it just shows a static site that refreshs.

Good choice, however the number of supported languages is limited to things with language server or treesitter support. Meaning languages without this, like asciidoc, is not supported and might never be

I recommend to start with kickstart if you prefer to customize https://github.com/nvim-lua/kickstart.nvim or Lunarvim for a full IDE experience to see what's possible and go from there https://www.lunarvim.org/de/

Most works out of the box then. Start there and customize further to your needs

That looks promising, especially since my current status bar is also just a collection of shell scripts, so that might be easier to switch

I forgot one essential tool, where I need a recommendation for: spotlight. I use it to switch quickly between applications or to folders. Keyboard shortcut, first letter of the application name and enter... I know there are solutions, but I only heard from Ubuntu, which I don't want. Anything simple and fast you can recommend?