Hello,
This demo https://xstore.8theme.com/elementor/demos/grocery-market/ was create using Elementor plugin. Do not activate WPBakery at all. Go to settings of the Elementor > Post types > enable editor for static blocks, then you will be able to edit content of the Footer using Elementor.
In your case, there can be a conflick between 2 editors, so provide temporary wp-admin access in case you can’t see changes even after using Elementor.
Regards