I did actually try zip bombs at first. They didn't work due to the architecture of how Amazon's scraper works. It just made the requests get retried.

At least, not with the default rules. I read that discussion a few days ago and was surprised how few callouts there were that a WAF is just a part of the infrastructure - it is the rules that people are actually complaining about. I think the problem is that so many apps run on AWS and their default WAF rules have some silly content filtering. And their "security baseline" says that you have to use a WAF and include their default rules, so security teams lock down on those rules without any real thought put into whether or not they make sense for any given scenario.

I think that's the point, you'd use robots.txt to direct Googlebot/Bingbot/etc away from countermeasures that could potentially mess up your SEO. If other bots ignore the signpost clearly saying not to enter the tarpit, that's their own stupid fault.