This Video by Michael Schultz shows you how to integrate the functions.php file code to disable the Gutenberg block editor in WordPress 5.0, and use the previous WYSIWYG editor.
Here is the Code for reference, used in video:
Implement the below code to Disable Gutenberg Editor Cleanly and Use Old Editor (However, we recommend to take all precautionary measures, before makign any change in the theme code)
Here’s the Video
This Video is the copyright product of Michael Schultz and TechnoMusk holds no rights to this Video