How to remove subcategories and how to add them?

Question

PHP

How to remove subcategories when I only display main categories?

$all_categories = get_categories(array(
    'taxonomy'     => 'product_cat',
    'show_count'   => 0,
    'pad_counts'   => 0,
    'hierarchical' => 0,
    'hide_empty'   => 0,
));

Also, when you click on any category, it should be displayed on the subcategory page.

$all_categories = get_categories(array(
    'taxonomy'     => 'product_cat',
    'show_count'   => 0,
    'pad_counts'   => 0,
    'hierarchical' => 0,
    'hide_empty'   => 0,
    'child_of'     => '15'
));

'child_of' => '15'here I specified the category id, should I do this for each category through a condition or is there another way?