I set it to “high” with FSR “quality mode”. In non-intensive areas, I get ~80-110 frames but, e.g., in the New York discovery flight, frames can drop to the high 20s. I tried setting VSync to 50% refresh rate but that doesn’t get rid of the drops. No VSync doesn’t get rid of them either.
Hello, I am no expert, but I am sure loads of people here can chime in. It would be convenient if you provided your full system specs, it could well be that you are CPU limited in high demanding locations for all we know 
Ryzen 5 5500
16GB RAM
That sounds about right. On my PC with a 5900x cpu and a 7900 XTX I get ~80-110 fps in non-intensive areas, but in New York City frames can drop to the 50s. I’m using a 4K monitor with HDR10 on.
Lower fps is normal in high density areas/airports.