You are likely main thread limited meaning your GPU is not fully utilised, it’s waiting for the next frame information to be passed form the CPU the whole time.
Pretty normal with a powerful GPU in FS2020. You can use Dev mode to display FPS/diagnostic information to see.
You can raise settings, render resolution to get ‘more’ utilisation out of the GPU. Alternatively you can lower settings like LOD to lift CPU performance, raise framerates and likely increase GPU utilisation that way.
However, best perceived performance tends to come from fixing/limiting frame rates and so giving a very consistent frame rate, which we percieve as ‘smooth’ even if FPS is lower. YOu will also not fully utilise your GPU in this circumstance.