I'd like to rephrase as, "don't deploy LLM generated code if you don't know how it works (or what it does)"
This means, it's okay to use LLM to try something new that you're on the fence about. Learn it and then once you've learned that concept or the idea, you can go ahead to use same code if it's good enough.
I've seen a whole flurry of reverts due to exactly this. I've also dabbled in trusting it a little too much, and had the expected pain.
I'm still learning where it's usable and where I'm over-reaching. At present I'm at about break-even on time spent, which bodes well for the next few years as they iron out some of the more obvious issues.
What you're asking is a bottom-up approach and I'm not sure if it can help you in this context.
What you may get in return is a bunch of theoretical concepts that may or may be relevant to your case.
Try to find answer using top-down questioning. Perhaps ask questions to the party that gave you this feedback (Ask yourself first), Was I too slow? Did I miss out on an important context? What other specific thing was noticed?
This means, it's okay to use LLM to try something new that you're on the fence about. Learn it and then once you've learned that concept or the idea, you can go ahead to use same code if it's good enough.