Renaming Theme folder using Child Theme

what about that way (in addition) in the docu via: avf_dynamic_stylesheet_filename
see: https://kriesi.at/documentation/enfold/personalize-theme/

All of the Styling options you set in the theme’s Styling options are saved to a file in your uploads folder called enfold.css. If you have changed the theme name or something like that you may want to rename this file to better reflect your own branding. You can use the following function to do just that:

function avia_change_filename($stylesheet){
   return 'custom_name';
}
add_filter('avf_dynamic_stylesheet_filename', 'avia_change_filename');