I did some experimenting today and have narrowed the issue down to the GPU drivers. For starters, the integrated Intel HD 620 graphics can't be enabled. It doesn't show up in the device manager and any attempt to install the drivers directly from Intel
fails as the installer allegedly won't find the graphics card.
This leads to even the simplest tasks running unnecessarily on the NVidia GPU. In my case, it constantly runs at over 55 degrees celsius and keeps the fans running at medium to high the entire time. I tried to update the drivers with the latest ones from
NVidia, but apparently Microsoft won't let you do that either - "hardware not found" every time. The ones that come installed with the Studio 2 are fairly dated.
Microsoft has also decided to remove the NVidia control panel, so no way to control the GPUs behavior.
So all of this seems to be a software issue - I hope someone from the MS hardware team reads this and can offer a timely fix, as the problem is driving me absolutely bonkers. I'm very close to selling the machine and going back to an iMac.