Inside this .bz2 [1] there is a directory called bh_routes/bh_vps_120/ and in that there are many AS files named for many of the VPS/Server providers. If you site does not need inbound connections from such places that is a starting point to reduce the traffic a bit. Each file has a comment with the AS#/whois name if you want to double check who/what you may be blocking. Not perfect but it may make a dent in the traffic. Or ask Cloudflare if they have an option to block anything that is not residential or LTE wireless. Even if you want to allow bots, maybe have a "shields up" mode where bots are sent away until the attack passes.

Another potential option would be to configure nginx IP limits using the Cloudflare header that represents the IP, set the shared memory size rather high and return 525 to the IP's exceeding a limit to avoid them hitting your redirect rules though it feels like CF should be able to create something custom for this assuming its a paid account.

Any IP that is not VPS/server should be archived for the feds as they are working on shutting down residential proxy providers including apps that are turning peoples cell phones into proxies.

[1] - https://nochan.net/b/Internet-Crap/20260606-How-To-Block-Som...