Keyword cannibalization is a huge waste of time, when focus keyword optimization for the category page is all that is required to increase SEO value. Using a strong focus keyword for your category page avoids competing for search results. Although the focus keyword should apply strictly to the category page, it can be used elsewhere in the text of content pages.
A focus keyword or phrase is used to evaluate the SEO title, H1 tag, body copy, etc. Essentially, it informs optimization by identifying for what a post or page should rank. Unless a website has some amount of reigning authority (two different pages easily ranking in the top 10 search results because one page is already ranking for a specific keyword), it is probably not a good idea to use the same focus keyword for different, however similar, pages of the same website.
Not ranking anywhere indicates a need for improved and updated content with a more effective focus keyword. Optimizing with the same keyword twice instructs search engines that either page with that focus keyword can appear as a search result, thus limiting traffic to one or the other page offering slightly differing content (Yoast).
Although the ultimate goal is to generate one amazing piece of content that collects all backlinks and effortlessly dominates search results, such cannot always be the case. Creating diverse content for an online shop or business with similar offerings can be tricky. Everything needs its own page, but is far too similar for different focus keywords or phrases. To maximize SEO value, It is generally better to use a focus keyword only once.
Hence, focus.
Well then… All other content on a single website must be screwed in terms of SEO value, right? WRONG!
In such cases, the category page is more important for optimization. Spend some time mastering the category page that links all similar products or posts, rather than worry about the individual pages. Specifically, ensure that all pages with similar stuff link to that category page with preferred keywords. As a result, traffic on similar content pages boost the search engine ranking of the category page.
Always be smart with the way you publish and structure content for search engines! A well thought out site structure is always important when it comes to search engine rankings, particularly with sites offering similar content.
Cluster content so you can topically can have a stronghold on one page. Thematic topics should all be connected in a way. Always employ the use of LSI (Latent Semantic Indexing) keywords as semantics are important.
Lastly, understand architecture. How is your page being created? Why? Don’t publish 10 times about the same topic. Instead try adding to the same post when new, relevant information becomes available. For example MOZ published an SEO guide which was published years ago but is continuously updated!