You may want to take a look to this in case you have latest Windows 11 23H2 installed. I did some tests today and CPU utilization graph returned to the former one we had with older game versions, being steady instead of a rollercoaster and reducing the extreme freezes we have with SU14.
This may be an issue with CPU P+E cores after latest Windows patches, being the P cores not used for games or intensive applications as expected or at least all the time. Maybe it was configured on purpose as part of a new energy saving feature but current Windows default configuration clearly has a negative impact in games performance and in particular in MSFS case as far as I have seen.
The fix simply modifies power management profile, which is part of standard Windows energy saving features, to force P cores on long threads (the ones used by games and intensive applications most of the time), leaving the E cores for short threads (secondary tasks), as it should normally be. It can be adjusted as you prefer or restored anytime you want, so it’s totally safe. That approach is indeed the expected one by design on CPUs having such types of cores, so there was no reason to change it.
Cheers