If you want to improve your products-in-categories management Magento 2 Dynamic Categories extension is the right solution. It allows you to create categories that generate products automatically based on product attributes.
Products removal from the category or other categories, adding cart price rules products to dynamic categories, product preview, and dynamic category rules attribute options help you simplify product assigning to categories.
Check this video to learn more about those options and find out how the dynamic category rule is created.