Looks like exporting from OneNote to markdown is not ideal, so if you’re not willing to go the copy-paste route or manual entry you may want to look elsewhere. That said I think it’s a toss up between logseq and obsidian. Of course one is FOSS and one is not so keep that in mind if it’s a dealbreaker. They take slightly different approaches to the minimum size of a piece of content. Obsidian uses a page format (like joplin) while logseq is indexing on something closer in spirit to a paragraph (though these can be of arbitrary length). This has a couple of unique benefits like being able to automate the creation of flashcards and similar review tools. Both have vibrant plugin communities.
Looks like exporting from OneNote to markdown is not ideal, so if you’re not willing to go the copy-paste route or manual entry you may want to look elsewhere. That said I think it’s a toss up between logseq and obsidian. Of course one is FOSS and one is not so keep that in mind if it’s a dealbreaker. They take slightly different approaches to the minimum size of a piece of content. Obsidian uses a page format (like joplin) while logseq is indexing on something closer in spirit to a paragraph (though these can be of arbitrary length). This has a couple of unique benefits like being able to automate the creation of flashcards and similar review tools. Both have vibrant plugin communities.