So I got a 3090 ftw3 hybrid Rev. 0.1 and temps are all fine except the hotspot temp.  It'll show while gaming 100-104C in gpuz sensors but gpu core and mems temps are fine.
 
I looked online and found different answers on what the hotspot is measuring from it's the hottest component to the memory controller, etc, etc.   What exactly is the hotspot measuring?

Took the card part and there was a dry spot right in the center of the gpu die and the paste on the edges where they touch the mem plate was pretty dry too.   Put on some FuzeIce Plus.   Seems to have fixed it.