How do you deal with DDoS attacks on your infra / sites? Especially ones from residential proxies or vpn networks? These are the hardest to defend against as they often are relentless and no amount of proof-of-work, captchas or otherwise seems to stop them from coming. I don't think it's something you can easily block at any firewall level, the sheer volume of IP(s) and Subnets is too much.