Ideally you should also match the FOV, so it would be like this:
https://www.mouse-sensitivity.com/?share=d8c1057204664f7652dcfd095c97de14
The calculation is based on MDV 0%, which if your settings in Vanguard is MouseHorizontalSensibility = "5.2, MouseMonitorDistanceCoeff = "0.00" , ADSSensitivity = "0.7" and all ADS to ADSLowZoomSensitivity = "1.42857" will be a perfect match.
R6 uses MDV 0% by default, so that's why you get the same value for all scopes.