Then block all of Amazon, Meta, or wherever botnet/crawling traffic is coming from that doesn't honor robots.txt, sends DDoS reflection traffic, submits SMTP messages (in large volumes, not just probing) for domains they're not authorized for with SPF, or whatever else applies to the protocol you're using

If they can't keep their ranges clean to a reasonable degree, their customers will need to move if they want to access your part of the internet. New sign-ups will always be hard, so some amount of abuse is expected, but if it's the same abuse traffic for weeks after you've notified them, well, it stops being your problem at some point