Phanteks p400 + fractal design Celsius 240mm + i5 9600k.

Okey so just upgraded computer and got a phanteks p400, i5 9600k, z390-f and fractal design Celsius 240mm. I mounted the radiator and fans at the front. Couldn't mount it at the top cuz the motherboard is in the way (should've looked in to it before buying). So I got radiator in the front with 2 fans, 1 fan at the top and on in the back. Every fan blowing out. I am new to doing a good airflow with the fans. What would be the best way to use the fans for a colder cpu. Currently at a stress test with Prime95 my cpu gets to 100° Celsius with an OC at 4.8ghz and a voltage at 1.2V. I think that is way to high even though the fans ain't perfectly mounted for the best airflow. Is it just my dumb airflow situation making it so hot or is it something else? Sorry for being a newbie. Help would be very much appreciated.

Edit: anyone else have the same case, cpu and cooler? If so what's your result?