Basically same here. Also in my case, Task Manager shows that the Power Usage is Very high, with CPU usage above 80%. Relevant screenshots are attached.
I already tried doing a Safe Boot of MSFS 2020 but the same problem occurs.
If I attempt to start MSFS 2020 again, it won’t start. First I have to go into Task Manager, end the Process; then after that MSFS 2020 will start and appears to run properly - except the next shutdown attempt ends with the same artifact of the FlightSimulator.exe process not actually ending.