That is definitely wrong. Install HWInfo64 and check what voltage it is idling at. If you have CAM running, try closing it and see if the voltage goes down. I had a program on my previous keyboard that would keep my 3800X at 1.475v and people had that issue with Corsair's software too. If that is fine, check other programs you might have active. Finally try re pasting the cooler.
Repasted the CPU (KRYONAUT Thermal Grizzly) - I'd spread a thin layer all over, but when I lifted the heatsink to check, it was obvious the paste was too thin in some spots. Added a little more and reseated the cooler.
Ran HWInfo and immediately saw CPU idle temps of 32°C, so an instant improvement.
I've double checked the Windows power plan is on the Ryzen optimization setting and set Gigabyte's fan software to an aggressive curve.
Just running Hellblade: Senua"s Sacrifice (4k, all settings on Ultra) to check performance - GPU is at 65°C and CPU at 53°C.
I'll play a bit and check again - but a far better result than last night.