Make sure the game is using the Nvidia GPU and not solely running on the CPU.

• Right click on FPV.SkyDive in the Steam library → Properties → General
  
• Insert the following text [command] in the "launch options" field*:
  
  __NV_PRIME_RENDER_OFFLOAD=0 __GLX_VENDOR_LIBRARY_NAME=nvidia %command%

* If there's no noticeable difference one might have to change `0` to `1`. To be sure which number is assigned to the GPU, run `nvidia-smi` in a Linux terminal which will output:

* I don't have an AMD GPU, so no clue if there's a similar command for those, sorry.

Ideally the ingame FPS should match the FPS of the monitor. In my experience limiting the game's FPS to 144, matching my monitor, results in the smoothest experience.

Conversely, when I set my monitor's FPS to 165 while the game is running at 144, it feels off, like there's some sand in the bearings.

Obviously turn off vertical sync. Motion blur isn't really necessary either, and depending on how good the GPU is one might as well turn off anti-aliasing because it's a huge strain and real life FPV goggles don't have anti-aliasing either; in a sense it's a more realistic simulation without it. Furthermore I enable the FPV.SkyDive camera noise setting to closely match reality.

Another performance boost might be to lower the field of view because then there's less on screen that the GPU has to render [calculate for].

If the game suddenly starts to perform significantly worse, after an update for example, it might just need a complete reinstall.

I'm using Linux distribution EndeavourOS[endeavouros.com], which is basically an easy installer for Arch Linux. When first launching EndeavourOS from a live USB it gives the option to between ≈"normal" and a ≈"machine with a recent Nvidia GPU" [can't recall the exact text]. The latter option takes care of installing Nvidia drivers automatically. In any case, most Linux distributions should be able to handle it, but it might just take some extra tinkering depending on the distribution.

Hope this short guide helps someone someday. Enjoy.
🐝