A mod I made that allows you to customize zoom sensitivity recently got approved for official realm.
By default the mod makes zoom sensitivity scale with focal length/zoom ratio but you can change it to scale by a custom FOV aspect ratio (aka monitor distance).
The game uses vertical FOV to scale by default.
https://steamcommunity.com/sharedfiles/filedetails/?id=1498189723
Unrelated to sensitivity but using the same math I also made a mod that fixes crosshairs: https://steamcommunity.com/sharedfiles/filedetails/?id=1569650837