Keyword Cannibalization - trying to build topical authority in my space

I'm new to this space so go easy on me! I'm trying to optimize a dive center's website. It has been up and running for about 10 years with 90 pages of random blogs that have been typed up over the years with no actual SEO strategy involved. Most just like "day in the life of" but more recently they had tried to publish more "how to" type stuff. I came in to clean up the content a bit, find any pages that are working ok but that we could optimize, and create new content. As I iron out our product pages to try and optimize them for their specific keywords I am also trying to think about topics which will support them and help rank higher. What I'm getting stuck on a bit is this whether i'm writing content that will cause keyword cannibalization. So for instance we have a product page SSI Divemaster Course \[Location\] If I am to write a blog article that is "how to become a divemaster" is that a distinct enough long tail keyword that I could write a blog post on or should all the information of that blog post really be included in the main product page? I'm having trouble deciphering what will cause keyword cannibalization and what will not. AI said yeah go for it it is fine but my yoast plugin is telling me I not to link to other pages thats include SSI Divemaster Course when I am trying to get the blog page to rank for something that also includes the words divemaster course, even though the full longtail KW is different. I don't know what I don't know, so perhaps the answer here is crystal clear for some. Any insight is helpful and if anyone has any resources on spaces to learn more about content creation and building topical authority send them over. Thanks!