Thanks for the reply! In terms of on-page SEO should I mention those keywords more in my content? E.g. create blog posts optimized for those keywords. Or this will not affect my product landing pages?

What steps for on-page SEO optimization should I do first of all?

I have some landings which rank for keywords only on 20+ positions. Those pages appear in search results, but the user doesn't see them as they are on 3-5 pages on Google, and I get 0 traffic. How can I improve these positions in terms of SEO? Ideally, I want to rank in the top 10.

What to do if my product page has 200+ internal links on it representing shapes for this product? How to reduce them to improve my SEO? Should I paginate them or update the site structure?

Declaring the duplicate pages canonical will be regarded as the best. Too many redirects are harmful to the SEO.

I have 1000+ duplicate pages, e.g., www.mydomain.com/category/subcategory/page-example and www.mydomain.com/page-example. What would be better to set canonical or do 301 redirect? I'm not sure if too many canonicalized pages will not seem strange to Google. Let me know the best approach, please.