first, the ips of all vpn providers are known, the problem with the cheap/free ones is that they spy on you.

instead of blocking ips use proof of work for those sus ips https://github.com/TecharoHQ/anubis

(it’s the anime girl that checks if you are a bot. :3)

it drives the cost of crawling at scale high up while being minor for individual, “legit” requests

all the cool kids are using it