MSFS + 16GB of RAM and a 3070 running 4K on high… did you expect WarThunder?
I have 10c/20t, 128GB DDR4, and a 3080 yet you still have higher expectations than me 
Try dropping the resolution scaling down to 80% or so, cutting all traffic in half, and running lower terrain level of detail to 100 or below. Give the camera a few spins if you are already flying when testing to level out the fps.