I guess I'm an outlier then.

AI has radically improved my ability to parse and understand new codebases, to validate my hypotheses, and to work in complex systems.

I wish I knew what I was doing differently than almost every developer.

You're not an outlier. The anti-AI stance is likely to be vocal online. They're quite incentivised to talk about it. Most programmers have adopted AI assisted programming (my own assertion) and most will feel like you and I, that it is useful. I know of a few programmers personally who hate it, but even they use it. There is no going back.

It is pretty obvious that when you come into a large incomprehensible codebase (which most are), AI will be able to reason about it more quickly and guide you through it.

I switched away from my work for a few minutes, but at the very moment I'm using AI to summarise some spaghetti code in a particular area in our codebase, so I can refactor it.

And that is my style of working at the moment. AI coding is useful, sometimes amazing, but sometimes irritating, and from experience I think just telling it to refactor this area would result in something I'm not happy with. So instead I'm getting a handle on it, I'll form the design I want, then tell it to do it. I have a feeling a lot of complaints are from people who won't bother to do that.