I like this extension which remains simple. It lacks some features that would make it the perfect application for synchronized notes: labels/tags to organize notes, archive, list with checkbox (for a to-do list)... But above all, keep a simple application focused on the essentials. Too many note-taking apps have become monsters of complexity.
I also use the app on Android. By the way, I have a permanent bug. My Mozilla account is in 2FA. I'm logged out every 24 hours on the Android app. It's not convenient to have to log in so often to update the notes. No problem on my different Firefox deskptop.