Product Category & Features During Product Creation

We are looking for an easy way for the vendors to create a product; the default categories and subcategories are shown in one field. It is not easy for any new vendor to select the categories when creating a product, especially when the category list is long.

Besides, the features can only be selected AFTER the product is created; it is like taking two steps to create one product.

We want to separate the current product's main category, 1st level subcategories, and 2nd level categories in the separate fields and let the vendor select the features while creating the product as in the image below:

Product Creation concept:

We keep the current main category field but only showing the main category for selection, but we create the 2nd and 3rd level subcategories fields. The idea is to display and self-populate the related 1st subcategory when the main category is selected. And similarly to the 2nd subcategory when the 1st subcategory is selected.

Below is the image illustration:

I want to know if there is already some add-on that can achieve the above.

Out of curiosity, I am unsure why the default cs-cart features are only showing AFTER the product is created.