You're definitely not alone in that struggle. While BigCommerce is a solid platform, it's not really designed to handle complex product information management on its own. Many people supplement it with a dedicated PIM system to streamline things. I recently read this article about PIM for BigCommerce, and it gave me a much better understanding of the options available:
https://www.webpronews.com/pim-for-bigcommerce/. It sounds like integrating a PIM can really improve efficiency. It can help especially with large catalogs with lots of variants and attributes. I hope this helps you with your decision.