@All: I really try to understand why Ali has so bad thermals in sandwich mode but I can't get. Just in this moment I retest it on my 3900X Ryzen with an RTX 3080 FE and I got really good temperatures.
Here is my test as a reminder:
Maybe he will take a look at it again.
I did think the PCB was supposed to have a cutout, so that certainly did not help.
But he uses an Intel 10900K, so of course it turns into a furnace. No one in the SFF community should even think about getting Intel at this point.