Ask HN: Where to learn the specifics of how GPT4-quality models are created?

I have never followed AI/ML work. In my experience, all the AI/ML workers I've encountered seen to throw stuff at the wall and see what sticks. Clearly, that is not how the GPT-3/GPT-4 models were built.

Is there a resource that explicitly explains at a technical level the thought process behind a full implementation of a model like these? For example, why they chose to add an X-type layer here, or what layers they may have tweaked and why to improve 3.5 to 4's quality?

I understand OpenAI is closed source. But I'm sure there isn't some secret sauce that only employees there know about that makes these models happen, so where does one learn this?