For those who don't know it: you have logseq as a true open source competitor of Obsidian. Although it's not as much an editor as an outliner; notes are strong

For those who don't know it: you have logseq as a true open source competitor of Obsidian. Although it's not as much an editor as an outliner; notes are strongly hierarchical, and it's difficult to use for writing plain markdown files. But that shouldn't be a problem if your main need is note-taking.