I resonate with OP a lot, and in my opinion, it's not about the code quality. It's about the effort that was put in, like in each LOC. I can't quite put it in words, but, like, the art comparison works quite well. If someone generates a painting with Gemini, it makes it somewhat heartless. It may still be good and bring the project forward (in case of this PR), but it lost every emotional value.
I would probably never be able to review this kind of code in open source projects without any financial compensation, because of that reason. Not because I don't like LLMs, not use LLMs, or think their code is of bad quality. But, while without LLMs I know there was a person who sat down and wrote all this in painstaking work, now I know that he or she barely steered a robot that wrote it. It may still be good work, and the steering and prompting is still work and requires skill, but for me I would not feel any emotional value in this code, and it would make it A LOT harder to gather motivation to review it. Interestingly, when I think about it, I realize that I would inherently have motivation to find out how the developer prompted the agent.
Like, you know, when I see a wooden statue of which I know it was designed and carved by someone in months of work, I could appreciate every single edge of the wood much more than if there's a statue that was designed by someone but carved by some kind of wooden CNC machine. It may be same statue and the same or even better quality, and it was still skillful work, but I lose my connection to it.
Can't quite pinpoint it, but for me, it seems, the human aspect is really important here, at least when it's about passion and motivation.
Maybe that made some sense, idk. I just wrote out of my ass.