How can you analyze the potential growth in the product category?
In order to analyze your product categories and catch the trends, you should be sure you have the correct set-up on Google Analytics. You can control your shopping funnel setup for analyzing your product categories.
If you have already the correct setup, you are able to analyze each of your category views, and their click rates moreover if you blend it with your Google Ads data you can reach how much money you spend on it.
However, this requires having a systematic approach to continuous monitoring and evaluating performance for catching opportunities.
But this process can be automated in different ways.
I researched this and found some sources for automating product category analyses, you can check out these;
https://insight.heybooster.ai/catching-the-growing-product-categories/
https://www.clootrack.com/knowledge_base/what-is-product-category-analysis-and-why-is-it-important
https://www.revuze.it/blog/what-is-product-category-analysis/