I'm having the same issue with an Intel I9-10850k .
I also have dual boot to an Ubuntu. When my CPU is idle on Ubuntu, temps are around 45 degrees Celcius. On Windows 11 they scale up quickly to 85, 90 degrees while idle (CPU usage around 2% ~ 3%).
Watching videos on Youtube using chrome with 2 monitors and 20+ tabs opened in Ubuntu rises the cores temperatures to around 75 degrees and the temperature drops back to normal 40 ~ 45 degrees when I close Chrome. In a fresh Windows 11 installation on the other hand, with a single monitor and only one Chrome tab opened (No extensions are installed in Chrome) makes some cores reach the critical 100 degrees temperature and the temperatures never drops on windows 11. This also happens for other browsers like their own MS Edge and Brave.
I also changed the thermal paste twice, and cleaned the heatsink. This overheating issue is definitely something Windows 11 related. I'm Wondering if I can sue MS if their OS fries my CPU.