hey folks,. got an Airflow question,.. trying to sort out best placement for my KINGPIN 3090 and a CPU 360mm AiO,.. my case is a Raijintek Evo with room for 360 rads on top and front,. 1 140mm in the rear and a 360rad/fan slot on the side panel,.. any suggestions for best flow direction would be greatly appreciated,. thanks again!

Normally having cool are from outside of the case blow across the radiator will give you the lowest (best) temps
 
Mounting those AIO coolers so that the hoses are at the lowest point of radiator, yet the radiator are above the center line of the device (GPU/ CPU pump) is what you need to achieve.
 
Size of case & the "length of the hoses on the AIO" are the limiting factors
 
Which specific Case (there are several Evo models) do you have?