KeepNote vs CherryTree
Both KeepNote and CherryTree are old-school open-source cross-platform note-taking apps.
KeepNote
With KeepNote, you can store your class notes, TODO lists, research notes, journal entries, paper outlines, etc in a simple notebook hierarchy with rich-text formatting, images, and more. Using full-text search, you can retrieve any note for later reference.
CherryTree
CherryTree is an open-source hierarchical note-taking app, featuring rich text and syntax highlighting. It stores everything in a single XML or SQLite file.
Fan of note-taking apps? 🤔
Maybe Paper is what you're looking for.