Thanks, updated now!
Correct, for most the in-game is probably accurate enough. But note that if you use a very low sensitivity, say you want to set it to 2 in-game, this can be as much as 0.029 in the config file, which is significantly higher.
You can do like this, and just adjust the WPS until the calculated DPI is 3200:
https://www.mouse-sensitivity.com/?share=c04fc1a15389c33438169a9328a69ad8
Sounds like maybe an issue with either your mouse driver loading a different DPI, or maybe some game setting you have modified that impacts the sensitivity (like m_yaw?). Are you using any mods to change FOV or something like that?
These games use the same "standard" sensitivity as CSGO etc, so it's a well known formula.
Just tried it now to be sure, and it works as intended. The correct selection for you is the "5" in WPS settings.
If it's not right, make sure you have turned off "Enhanced pointer precision".