Homepage showing more than 6 categories

Hello all,
I would like to display 8 or more categories on the Storefront homepage. By default the storefront theme shows 3 categories. I have included the following snippet from this site in the forum in the function.php:

add_filter('storefront_product_categories_shortcode_args','custom_storefront_category_per_page' );
 
// Category Products
function custom_storefront_category_per_page( $args ) {
 $args['number'] = 8;
 $args['columns'] = 4;
 return $args;
}

It works, but only 6 categories of 8 are shown. I don’t understand why. Do you have any idea?
Thank you for help.
AnaLisa

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