eventually throttled by OAI or Anthropic themselves

Indeed, they use an edge SSL Bump proxy that is already bandwidth limited and has to speak real HTTPS.

I do not focus too much on IP addresses but rather the behavior that they can not hide. LLM's can help you spot this behavior. Good LLM vs. Bad LLM. Gemini knows a few tricks but you have to coax it out of them. It seems to not want to overload people with information. That said there are some good IP lists that can be used in blackhole routing tables, nginx geo tables, etc...