This is an old topic and you’ve probably moved on but for anyone that’s looking for the same type of thing.
The first thing I ask is what will having a different field group for each category give that that having the same field group on all categories won’t.
If you still want to do this, you would not create a new field group every time a new category is created, you would create some custom php code that would run and create a field group and fields for each category that exists.
I’d start by exporting a field group that’s attached to a specific category first and use this for an example. Then I would add an function that runs on WP init
add_action('init', 'add_category_field_groups');
function add_category_field_groups() {
// use get_terms to get a list of categories
// https://developer.wordpress.org/reference/functions/get_terms/
// loop through the categories and create a field group
// I would set the group key to something like
// "group_termid000{$term->term_id}"
// see https://www.advancedcustomfields.com/resources/register-fields-via-php/
}
Hope that helps someone
