I had the same issue with a fashion store site — categories like /mens-boots and /summer-dresses were just ignored at first. What helped me was using a resource that analyzes both crawl and index status per URL. It let me see which categories were actually getting crawled versus just sitting undiscovered. I found that adding content blocks with unique text and linking them from top-selling product pages helped a lot. I resubmitted the top 10 non-indexed categories and 8 of them showed up in search within a week. It gave me the clarity I needed to fix things without guessing.