I’d like to be able to create a new block that lists subcategories of the current category the block is assigned to, with fillings of newest, emenu, plain, dynamic, rating, and a new filling type which allows you to sort the list order of the sub categories. Not exactly like adding categories manually now one by one. But to be able to resort the list of current sub categories.
Are you planning to do the work or are you looking for someone to do it for you. The capability you describe is not standard functionality of the cart.
I know it’s not standard functionality of the cart, and I may have my developer do it, the code isn’t to complicated to get all category ID’s who’s parent ID is the one selected when creating the block.
If you’re on a category page, all the sub categories are already available in template variables.