Ich arbeite gerade an einer Lösung, Abfragen aus China vollständig zu blocken. Dann sollte sich das Problem erledigt haben.
This might not be so much of help, as they easily can switch to proxies, so ...
What is the symptoms and the behavior exactly ? and by that (i know the symptoms of apache hitting limits,) but you should refine and might share here what is going on
are these requests leading to 403, 404, 401... HTTP errors, then it can handled elegantly by not answering with error, but with 200 and static page, this page could be huge with arbitrary text, yes literally arbitrary words from different languages, and this will cost them money and time, the most valuable for them.
is there http agent ? is it a browser ? if not a browser then again use the above or block the
IP for 5 minutes
is there a referrer ? if not and then again like above, this should be very effective.
what about cookies ?..
...
Now about the big file mentioned above, if it will be static then it will be handled once and cached by them, so you can figure a file on cloudflare pointing to a subdomain something like cdn.delphipraxis.net , just make anything coming for that subdomain return huge files cached on a cloudflare, free account might be enough.
In short examine these requests closely and think about it, there is tons of apache modules to help with stateless blocking, to stop crawlers and scrapers.
Also you might want to ask AI to help you there, these parts will be greatly helpful for you.
ps : mod_security, mod_evasive, mod_qos, mod_reqtimeout, mod_ratelimit, mod_maxminddb (or mod_geoip), mod_rewrite (UA block), ipset + iptables, fail2ban, specially
fail2ban would be very helpful to use, and if you are to block then block on network layer with ipset and/or iptables.