I have a 240mm and 360mm rad (30mm thick) on my 9600k 4.8ghz 1.216v and rtx 2070 2025mhz 1.00v undervolted and I get 50c max gpu and 60c max cpu. Warzone is very cpu hungry if your not using vsync. I get 60-80% cpu usage and 60-80% gpu usage at 60fps. looking at around 54c cpu max and 45 gpu max while in warzone. do you have vsync on and what res you running?
it'll come down to how the cpu block is mounted and which oriantation you have picked, the 9th gen chips from intel use a slightly rectangle die which if you look at the motherboard and how the cpu is installed, the waterblock should be installed so the fittings sit in the horizontal position side by side that way you maximise the cooling of the waterblock your using.
Also because you have a 280mm rad only, you'll need to crank up the fans a bit under load to try and help the tempratures and a critical step is to have good clear intake airflow into the case too, this is often overlooked and thus problems start to happen.
If you want the best tempratures then it all comes down to radiator's the more you have the better the cooling and you can run near silent under load if you have enough radiator capacity, if not then you need to increase fan speed.
just noticed your cpu overclock, what vcore voltage are you running to keep 4.8ghz stable?
its just above 1.3
could you help me to get 4.8 stable at 1.2 ?
I followed this guide and used the dynamic vcore?
https://forums.bit-tech.net/index.php?threads/9900k-5ghz-1-2v-guide-gigabyte-z390-master.353729/