Thanks again for your feedback.
the 100% on core 1 is indeed the maximum value reached at some point (as BeardyBrun also already suspected).
As you can see from the screenshot from HWInfo, the utilization of all cores at the time of the screenshot with 33 FPS was only <5%. Since these values fluctuate quite a bit, it is of course not impossible that the actual utilization was alternately around 25% per core.
According to HWinfo, the maximum cpu/thread-utilization averaged 21.7% over the entire measurement period, and 34.2% at the time of recording. Why doesn’t the CPU work faster, although only 33 FPS are achieved?
V-Sync is disabled.
For the screenshots I ran MSFS on my normal monitor at 1920x.
Normally MSFS runs on my external monitor at 3440 x 1440 resolution and 120Hz.