Wouldn't it be possible to block IP ranges that belong to known cloud providers? Normal people using the browser don't have such IP address assigned. You would be blocking as well other kind of visitors (scrappers and the like), but I guess that's a fair price to pay.
Let's forget about the small shady scrapers. What about OpenAI? My bet is that they run their scrapers in Azure/AWS/GCP. Let's ban the big cloud providers.