I’m also having performance degradation after long haul flights (more than 4h). At the app phase FPS drops to 16-20 (i have it caped and tuned to maintain 30fps stable with the sim VSync), but when closed and started the sim again… same scenery, same everything but now 30 fps without any problems.
I don’t have AI or live traffic, or multiplayer. No ground aircraft, airport vehicle and worker to 30%, Land and sea traffic to 40%.
After 3 years of MSFS still a pain in the ■■■ trying to debug why the sim does this things