https://nvim-orgmode.github.io/ is very good and very customisable while keeping consistent and open file file format that allows your notes to be easily stored and read by other apps.
Not very easy but not very hard either. Obsidian works with .md files they have close syntaxes to .org files that orgmode works with, but you will have to convert them.
I would also suggest searching for some neovim plugins working with .md files. That will allow you to directly import your files. Something like this maybe?
If you're used to markdown in Obsidian, you could look at vimwiki to use a similar syntax in vim. I find it works fairly nicely for standard notetaking, and is a lot faster to start than Obsidian.
It let's you create a wiki with links between pages.
Unlike obsidian, it doesn't put your personal data in the cloud.
Unlike the similarly named vimwiki it doesn't use a custom file format. It uses markdown. Although I think you can configure vimwiki to use markdown as well, but with reduced functionality of the plugin.