While I don't have anything too concrete, My best bet is your GPU.
The game has my GTX 1660S (A pretty old GPU) sitting at 40% usage and regularly spiking to 70+, Along with making it all toasty, Enough to make the fans go nuts.

As for RAM and CPU usage, RAM hasn't gone over 600mb once, And CPU usage sits so low that I have to dig through task manager to find it.

I can probably narrow the problem down if I knew what your specs were (You can check in the "Performance" tab in Task Manager), And you shouldn't rule out some fatal error that's happening for whatever reason.