Not sure if this will help you, and I have not done this with WC.
Some time ago I decided, not long after guberbug gutenberg was released that I would not be using it. I also at that time decided that I will not be using the standard “Classic Editor” area for content. The reason for this is that there is no guarantee that classic editor will continue to be supported. However, I believe that ACF will always include a WYSIWYG field that uses tinyMCE. I also believe that there will always likely be a way to disable the new editor.
So, I remove all editors. I am currently using classic editor to disable the new editor and I use ACF to hide the default content field and I create my own custom fields that includes a field for the content if the post type calls for such a field.
Depending on what I am doing I either just show this field in the template instead of “the_content()” or I create an acf/save_post action that copies this content into “post_content”. For use with WC I would likely go with the second option of copying the content to the standard location because that way I would not need to mess about with WC templates in order to use my custom field.
In your case I would likely have two fields in one group, “Full Descriptiosn” and “Short Description”
