When it comes to ADS sensitivity in Tarkov, your sensitivity setting is your 360 turn rate, no matter which scope you're using. So if you get the sensitivity right for ironsight, then your zoom sens will be too high because you're turning 360 at the same rate. If you get the sens right for a 6x scope, then your 1x red dot will be too slow.
As for hipfire sens, it is affected by your armor/helmet.
The only workaround I found to match ADS sensitivity is to lower the FoV. I noticed that when I played with 59 in-game fov, everything was fine, but when I switched to 74 FoV, then the difference between zoom levels became very apparent.