Running a 5080 in VR with an Intel 14900K, I've noticed something strange when flying at night with the A350, FPS is always halved.
I've been doing some tweaking with the ini builds A350 in FS2024, the fps tools I've been using have shown the above issue with the A350 in Aerofly.
FPS is locked at 90 with the quest 3, easily achievable in VR in the A350, when I switch to night, FPS drops to around 40 (slower than the inibuilds A350) If I switch to any other aircraft in Aerofly, FPS stays locked at 90 (day or night)
What is it about the A350 that differs? The A320 actually has better night lighting visually and better FPS.
I don't think my machine is the issue, as it's smooth as silk at an airport like Heathrow. I can be in the middle of nowhere with the A350, and FPS still drops to half at night.
It seems like a bug with the optimization. I may as well also add, along with night lighting, flickering when you move your head in VR, I've noticed entire clouds can disappear when you move your head 
This can cause nausea since the cloud is visible in one eye, invisible in the other. Am sticking to flying during the day or at night only with low visibility.