The cover has a stack that says "ngirx", and it's all a smudgy mess.

"Don't judge a book by its cover" is for people who don't actually read books. You can't necessarily tell when a book is good based on its cover, but you can absolutely tell with a high certainty that a book with a lazy, crappy, low effort cover is probably going to have a similar level of care and attention put to the contents. It's easily at least a 95% hit rate. Is not overly critical to see something presented lazily and assume it will also be lazy inside, and in this kind of field, I'd also expect that if the cover is AI generated, most of the content could easily be as well.