Obsidian

I've used Obsidian for a couple years. It's a very good note-taking app. Vault (a paid add-on) makes syncing across devices effortless, but other cloud solutions also work. Composing in markdown's fast: your hands never leave the keyboard. It stores notes in markdown, so there's no lock-in: you can open them in a text editor. Once a note is synced to your device, you can reliably get to it even when you're offline. Quirks are in tables (a bit clunky) and the outline (hard to find on phones).

Just started using this for a worldbuilding project, and I'm a little addicted to the Wikipedia style linking and the filepath display. Sometimes getting links to work is a little frustrating, and I don't quite understand how to use aliases correctly, but I think those are mostly me problems (or mobile problems, cause this probably works so much better and cleaner on a computer). I do want a way to quickly find empty files, cause I've left a bunch of them lying around.

I've loved this app for note taking across all of my devices. I use it for everything from day to day, projects, notes for my programming work, D&D, I mean you name it you can shape this app to work for it. The sync works almost scarily well. The only time I've ever found issue with it is syncing a device that's been out of sync for a while that ends up duplicating files that have been moved. If that's the ONLY issue I'm more than sold.