I dropped OneNote when the feature to add subtabs to tabs was removed. It used to be great, but compared to Obsidian it's clunky, slow to load, and my files aren't right there on my disk and editable/parseable with the CLI (which I use a lot).

Yeah, sure, you can do local notebooks in OneNote, but the UI is so intent on trying to trick you into storing things in The Cloud. Lock-in bad. Markdown good.