> Then you look up their IP address's abuse contact, send an email and get them to either stop attacking you or get booted off the internet so they can't attack you.
You will be surprised on how many ISPs will not respond. Sure, Hetzner will respond, but these abusers are not using Hetzner at all. If you actually studied the actual problem, these are residential ISPs in various countries (including in US and Europe, mind you). At best the ISP will respond one-by-one to their customers and scan their computers (and at this point the abusers have already switched to another IP block) and at worst the ISP literally has no capability to control this because they cannot trace their CGNATted connections (short of blocking connections to your site, which is definitely nuclear).
> And if that doesn't happen, you go to their ISP's ISP and get their ISP booted off the Internet.
Again, the IP blocks are rotated, so by the time that they would respond you need to do the whole reporting rigomarole again. Additionally, these ISPs would instead suggest to blackhole these requests or to utilize a commercial solution (aka using Cloudflare or something else), because at the end of the day the residential ISPs are national entites that would quite literally trigger geopolitcal concerns if you disconnected them.