After doing so, all of our logs, like ssh auth etc, are almost completely free and empty of malicious traffic. It’s actually shocking how well a blanket ban worked for us.
This. Just get several countries' entire IP address space and block these. I've posted I was doing just that only to be told that this wasn't in the "spirit" of the Internet or whatever similar nonsense.
In addition to that only allow SSH in from the few countries / ISPs legit trafic shall legitimately be coming from. This quiets the logs, saves bandwidth, saves resources, saves the planet.
(Yes, yes, VPNs and proxies exist and can be used by both good and bad actors to evade this strategy, and those are another set of IPs widely banned for the same reason. It’s a cat and mouse game but you can’t argue with the results)