Choose useful selections
Assess whether the combination has a stable assortment, a clear request and sufficiently independent content. For example, an important product type may deserve a separate landing page, while a random assortment and price range does not. Selected pages require stable URLs, titles and internal links.
Continue with: Canonical URLs: check consistency across the site.
Design technical rules
Define the order of parameters, the behavior of empty results, and the limits of combinations. Separately decide what can be crawled and what should be indexed: robots.txt, noindex and canonical are not interchangeable. Canonical is appropriate for the same or very similar content, but does not fix any uncontrolled URL generation.
Continue with: OpenCart catalog imports: SKUs, options and validation.
Check the catalog after changes
Compare the list of important landing pages with the sitemap and links in the categories. Test filters with empty results, duplicate parameters and pagination. Make sure the bot restrictions don't break the buyer's experience. Monitor URL growth and page exclusion reasons in Search Console.
Can I close all filters at once?
Technically yes, but you can lose useful landing pages. First, separate the content and demand pages from the technical combinations.