Across everything I've tried, Standard Notes seems to have the best set of tradeoffs, but they refuse to implement features (like add syntax highliters for modern lagnuages, if I remember correctly, they said that they would only consider it if I prove that thousands of people need it).
Anytype provides good privacy guarantees but they have crappy UX and, ergh, their app needs 5 seconds to start on a modern mac.
The whole notetaking apps market is a shitshow and a total mess. Don't waste your time and money on these half-backed subscription-based electron apps.
There are encrypted backups. Actually, backups are encrypted by default.
Notesnook also works offline by default so there's no need for a special mode. It's also, obviously, local-first since everything gets encrypted on your device. We don't have a lot of options there.
What "might be better" in the editor?