Hi I use TinyMCE (with react-tinymce module). As we know, TinyMCE is the default Wysiwyg editor on WordPress. What makes the code editor on Wordpress comofortable to use is it can automatically convert newline into <br>. Therefore the text looks much cleaner and easier to read.
Another good thing in the WordPress is the code editor is not displayed in popup, but in other tab. Displaying the code editor on popup (using the code plugin) is a bad design. Besides not comfortable, user can accidentally press esc or cancel button and lose all changes
So please consider to add those features