Hello, @Mario :),
If you want to show just the smallest price then you should use the theme option to show “From” for the variable product and there is no need to hide the price using the Custom CSS.
First of all, you have to remove that Custom CSS Code, and then you have to turn ON the option: “Show only minimum price for the variable products” under XStore >> Theme Settings >> WooCommerce >> Shop >> Product Styles: https://prnt.sc/0e99biCJm_cY
This is the only possible way.
Regards 8Themes Team.