Linebreeding isn't breeding to cousins. Inbreeding is not just about critically endangered breeds.
In fact if you asked 100 breeders for a definition of linebreeding, you would get a dozen different definitions... from linebreeding being any relative (ie aunt/nephew; grandfather granddaughter etc) that isn't first (mother/son, daughter/father, siblings) or closest connection. For others, like some famed geneticists, inbreeding is breeding dogs with common ancestors but no close relationship. (Lush: According to Lush, linebreeding pairs animals that are related to a specific ancestor, but which are little if at all related to each other. https://www.instituteofcaninebiology.org/blog/lush-on-linebreeding)
So when you talk about inbreeding or linebreeding, it helps to discuss what you mean by either term. For the rest ... this is the basenji forum. So if interested in breeding dogs, here are some initial articles.
From AKC: https://www.akc.org/expert-advice/dog-breeding/the-art-and-science-of-breeding-better-dogs/
Kennel Club: https://www.thekennelclub.org.uk/health/for-breeders/understanding-canine-genetics/inbreeding-and-health/
Inbreeding/linebreeding isn't necessarily good or bad. The truth is you can breed half-siblings, father/daughter and get MORE genetic diversity than from what looks like an outcross for generations. That is why understanding the COI (Coefficient of Inbreeding) matters. And why people like Pat and other good breeders understand the need for keeping line info, medical/health stats, and have a clue about the topic.
It isn't simple. Someone who starts studying now may have some inkling in 5 years. Making up simplistic comparisons helps no one.
https://www.thekennelclub.org.uk/health/for-breeders/inbreeding/