There is a way to repurpose plugin to something that will work with only server side information.
I was recommended this plugin in Discourse check the user IP for block list only on login. Discourse don’t really care about users IP, don’t ban user by IP by default (you need to do it manually), and about new user with same IP as banned one you can find only accidentally. Fingerprinting plugin not really helped me, because don’t check IP too.
Some overview page with users that have matching IP with banned accounts would be useful.
And also there is services like https://ip-api.com/ that allow to check if IP is proxy/vpn, can be another useful tool.
Besides IP discourse also have user email. I often see trolls with email from temporary email services, this can be indicator of a bad user too.