I switched to firefox-esr and will be happy to wait for tab groups and vertical tabs in the June/July version.

Ghostwriter is another good and simpler one for Linux

QOwnNotes is a fast loading, Qt based, plaintext editor that supports markdown and preview, plenty of helpful plugins, heavily customizable, has nextcloud support, supports workspaces in the form of note folders.

No affiliation but a happy user and also sponsor it.

This is just about the android app version. The desktop version still works and continues to live.

I was not even aware of this fork let alone a long timeline of existence. I am adding this onto my weekend project list. Thanks for the recommendation.