The original price for variations must be shown before the discount

add_filter( "adp_get_price_html_is_mod_needed", function ( $mod, $product, $context ) {
    if ( $product->is_type( 'variable' ) && $context->is( $context::WC_PRODUCT_PAGE ) ) {
        return false;
    }
    return $mod;
}, 10, 3 );

add_filter( "adp_get_price_html_is_mod_needed", function ( $mod, $product, $context ) {

if ( $product->is_type( 'variable' ) && $context->is( $context::WC_PRODUCT_PAGE ) ) {

return false;

}

return $mod;

}, 10, 3 );

Advanced Dynamic Pricing for WooCommerce

The original price for variations must be shown before the discount