User agent has been abused for so long, I forget a time when it wasn't.
Anyone else remember having to fake being a Windows machine so that YouTube/Netflix would serve you content better than standard def, or banking portals that blocked you if your agent didn't say you were Internet Explorer?
The AI scrapers are atrocious. They just blindly blast every URL on a site with no throttling. They are terribly written and managed as the same scraper will hit the same site multiple times a day or even hour. They also don't pay any attention to context so they'll happily blast git repo hosts and hit expensive endpoints.
They're like a constant DOS attack. They're hard to block at the network level because they span across different hyperscalers' IP blocks.