I have given up trying to serve China region. Its just endless attacks on the server making it slow. I have banned all traffic from China. I also configured some caching rules to try improve performance. Let me know if there is any difference or anything not working 100%.

Look into crowdsec, with the standard Http attack rules enabled. It should help mitigate some of the traffic and attempts.
I use cloudflare but China traffic was just all bots/illegitimate traffic and a crazy amount compared to everyone else and excessive rate of requests per second. Hope you are well by the way.
Oh that is a lot of traffic.
Thats wild