The most famous still maintained offline blog editor is Open Live Writer (https://en.wikipedia.org/wiki/Open_Live_Writer https://en.wikipedia.org/wiki/Open_Live

The most famous still maintained offline blog editor is Open Live Writer (https://en.wikipedia.org/wiki/Open_Live_Writer https://en.wikipedia.org/wiki/Open_Live_Writer , previously known as Windows Live Writer). It's Windows-only, which is a big improvement on average-joe-managability and multi-decade-perspectivity fronts to your idea of macOS-only app.