Most people do not need a clever notes system. They need somewhere fast to put things and a reliable way to find them again. These three cover nearly every situation we hear about.
1For most people
Apple Notes
Free with every Apple device
If you have an iPhone, you already have a very good notes app. Search finds text inside photos, folders and tags are enough for most people, and it syncs through iCloud without setup.
Free, zero setup, document scanning and photo search.
Free for personal use; Sync and Publish are paid add-ons
Obsidian is a folder of text files with a very good app on top. That means your notes will still open in 20 years. Plugins turn it into a calendar, a kanban board or a flashcard deck.
Files you own, fast search, plugins for everything.
Sync costs extra, and the plugin rabbit hole is real.