Not exactly what you asked, but do you know about ufw-blocklist?

I’ve been using this on my multiple VPSes for some time now and the number of fail2ban failed/banned has gone down like crazy. Previously, I had 20k failed attempts after a few months and 30-50 currently-banned IPs at all times; now it’s less than 1k failed after a year and maybe 3-ish banned at any time.

There was also that paid service where users share their spammy IP address attempts with a centralized network, which does some dynamic intelligence monitoring. I forgot the name and search these days isn’t great. Something to do with “Sense”? It was paid, but well recommended as far as I remember.