The tutorials listed here can vary a lot in quality. For the text editor section for example, there is a very good tutorial in C which guides its reader through the development of a kilo-like text editor with buffer management and everything, and next to that a YouTube video claiming to teach how to build a text editor in Python but is actually a (poorly coded) simple GUI using the text editor component of the Tkinter library. Well, it can serve as a Tkinter tutorial, but not as a "build your own text editor" one.