You realize this entire thread is about a pitch from a CDN company trying to solve an issue that has presented itself at such a scale that this is the best option they can think of to keep the web alive, right?

"Use a CDN" is not sufficient when these bots are so incredibly poorly behaved, because you're still paying for that CDN and this bad behavior is going to cost you a fortune in CDN costs (or cost the CDN a fortune instead, which is why Cloudflare is suggesting this).