Dudeee, thanks so much!
That was it. Didn't even notice there was an option like this. Even after resetting apparantely it still had those values hidden. Weird.
Goes to show it is once again the user not the machine :D
Programs like GPU-Z or HwMonitor don't have a problem at all reading the GPU Temp. But hwinfo does! I just don't know what I'm left to do.
I have my Asus rog strix 3090 on newest nvidia driver and also use the newest hwinfo (also tried older versions, also tried beta versions, also tried...