10700k idling at 40-55C, gaming 90-100C

[NickTheMajin]

I just built a new PC and want to make sure this is alright. 

 

I have an H440 case which is definitely not great for airflow. 

 

I have the stock three intake fans in the front, the stock exhaust fan in the back and added three exhaust fans on the top. My CPU cooler is the noctua NHD15 using one fan (2nd would not fit). While idling my temps are fine, between 40-55. When gaming though, my CPU very quickly will reach 100C and back off to 80-90 periodically going to 100C again. I've reset and reapplied past to my NH-D15 already. My room does get warm and my PC is about three feet away from my heater. No overclock. It depends on the game as well, Assassins Creed Odyssey routinely gets to 100C quickly, I never hit it on less demanding games, Cold Steel 3 runs at 60C. Cyberpunk hovers between 80-90C.