Game Mode essentually turns on notifications to “do not disturb” and fairly useless.
GPU Scheduling most suggest OFF
I may also suggest turning off HyperThreading however that does require entering and as some would say “tinkering” with the bios, read up on Hyper Threading and core use, make your own choice.
Also, as always, ensure you have all your updated motherboard drivers from the manufacturers website and or Windows Update.
While I only fly GA aircraft I seem to be getting about your performance level with a lessor PC 9900k/3060 full ultra, I even turn the few things up Ultra has down a tick and my final resolution is 6400x1200 so I’m pushing three times the pixels (primary scale 80%/secondary X1.1111121 from 5760X1080 original).