It is worth noting that MSFS is not only CPU intensive it also uses heat inducing AVX instructions which are rare in games.
This means that something with inadequate cooling (like putting a 9900K on a slim low profile air cooler) may actually run fine on GPU intensive non-AVX games but hit 100C on MSFS, the same temps you would get with that cooler running intensive tasks like rendering.
Your CPU may well run fine on other games and still have inadequate cooling when running close to it’s maximum.