I’m not comfortable with HTML Editor and would love to type directly in rich text editor. Is there any way to disable the HTML editor (the left box) in Joplin?
Not currently no, Joplin is a markdown not taking application, so that’s what’s available for now. There are plans to allow for a more rich text editing experience by integrating a new editor into Joplin. Hopefully this will be available in the near future.
For now you can try using an external editor such as typora which should be good for you. You can then hide the Joplin editor and just have the viewer by clicking on the toggle in the toolbar.