I've been using Zettle Notes with syncthing for a few years now. It syncs with my laptop as just a directory of markdown files that I also edit with Vim (plenty of good plugins like Vim wiki).

Logseq. It works with Markdown or Org. Joplin is fine but I've moved away from it for Orgzly Revived + Logseq mobile/Emacs Orgmode + Logseq desktop all integrated with each other to do some stuff Logseq and Orgzly cannot do alone.

You will not find a better option honestly I love my tools. Tried a lot of things and this is one that will grow with you and never overwhelm you if you respect it.

Particularly nice to be able to smoothly turn Logseq/Orgmode stuff into LaTeX stuff and use Emacs Zotero integrations. I can publish professional-level papers and articles of pretty much any kind, from the same system where I work on Minecraft mods and remind myself to do house chores so my wife thinks I am a genius (because I am). I could write an entire textbook with it. It feels like being forced to use a revolver for years, and then switching to an AR platform.

I am currently in the process of migrating my Google Keep notes over to a self hosted instance of La Suite Docs. It sounds like a big Google Docs alternative, but feels way more like a notes app.

AppFlowy