I use TiddlyWiki via TiddlyPWA. It’s an offline-capable PWA with builtin sync and encryption. It doesn’t have folders but it does have nestable tags. I don’t think it supports markdown out of the box, but I’m positive you can find a plugin to use markdown. Plugins are crazy easy to install in TiddlyWiki; you just drag and drop the plugin into your wiki window and confirm the installation.

TiddlyWiki via TiddlyPWA is what I use. I don’t know if it supports the S Pen and the notes are all saved in a single HTML file.

but it’s the one many first-time Fediverse users coming across from Twitter end up on.

That’s because it’s the only one ppl will mention as an alternative. Stop telling ppl to try mastodon, tell them to try firefish or akkoma.

Also, the jump effect is way overstated. Some users do end up moving to other software, but many more just leave because they don’t like mastodon.