This is terrible advice. I have a 9900k that isn't overclocked paired with 3090 at 4k and I am seeing zero bottlenecking or micro stuttering.9900k is not that great anymore and certainly bottlenecking that 3090.
Max CPU usage is 85% and that is only for a split second.
You need to step back from the keyboard and stop with your elitest veiws my boy