Somebody unified all the mouse sensitivities.
Just go through his INI and copy all the relevant settings to your's.
https://www.nexusmods.com/starfield/mods/656
Check the desc for the rest of the setup.
Code:[Controls] fMouseHeadingXScale=0.0100 fMouseHeadingYScale=0.0100 fPitchSpeedRatio=1.0000 fIronSightsPitchSpeedRatio=1.0000 fIronSightsLookSpeedPitch=2.0000 fIronSightsLookSpeedYaw=2.0000 fLookSpeedPitch=1.0000 fLookSpeedYaw=1.0000 bDampenFirstPlayerControls=0 bDampenThirdPlayerControls=0 [Combat] bAimAssistEnabled=0 bMagnetismEnabled=0 [Spaceship] bSpaceshipAimAssistEnabled=0
I definitely need to refine my spaceship controls in regards to the mouse otherwise I'm going to be using a controller for that part of the game.
The game technically doesn't release for another two days so I'm not going to be modding or doing much until we get past that and see what's what.