I’m not an expert but my understanding is that defending against DDOS requires immense infrastructure. Can a single site in its own achieve that with a load balancer or the rate limiting you mention?
Depends on the scope and scale of the attack. If you put a proxy server in front of the actual application server (or a series of proxy servers that were lightweight/cheap to run), technically speaking you could control it. Not an expert either but have relied on mechanisms like that in the past to help with traffic control.
Cloudflare already deplatformed people: https://tech.co/news/cloudflare-removes-service-8chan-2019-0....