Besides being unlikely to work for you even if someone is able to describe what makes their writing tick, most advice is written by people who don't understand how their writing works. This may be difficult to see for writing if you haven't spent a lot of time analyzing writing, but it's easy to see this is true if you've taken a bunch of dance classes or had sports instruction that isn't from a very good coach. If you watch, for example, the median dance instructor and listen to their instructions, you'll see that their instructions are quite different from what they actually do. People who listen and follow instructions instead of attempting to copy what the instructor is doing will end up doing the thing completely wrong. Most writing advice similarly fails to capture what's important.
One of the most common mistakes I see people make when looking at data is incorrectly using an overly simplified model. A specific variant of this that has derailed the majority of work roadmaps I've looked at is treating people as interchangeable, as if it doesn't matter who is doing what, as if individuals don't matter.
While being an extremely broad generalist can work, it's gotten much harder to "know a bit of everything" and be effective because there's more of everything over time (in terms of both breadth and depth).
...If you watch an anime or a TV series "about" fighting, people often improve by increasing the number of techniques they know because that's an easy thing to depict but, in real life, getting better at techniques you already know is often more effective than having a portfolio of hundreds of "moves". I've personally found this to be true in a variety of disciplines.
Perceptual: "They couldn't figure out what to do next", "they couldn't find the feature", "they didn't know they could click that button..." etc.
Domain-specific: "We need a way to jump back here because in their workflow this happens..."
In general, usability testing only catches type 1 perceptual problems. Because in those tests you take people out of the real world and assign them tasks. Usability testing doesn't catch domain-specific problems because they only come up in real life use.