Yeah that's true, but it's only for one guntype (which you could probably put up with).
Well whatever sensitivity you use for CS:GO should be your hipfire for COD. If you aren't using the same FOV (90) then you will need to convert between the games using Viewspeed v2. Then...
If you're playing COD WW2 you can convert from your COD hipfire sensitivity setting to your ADS setting using Viewspeed v2 and everything is pretty well good enough.
If I'm correct, BO3 and Infinite Warfare use 100% monitor match to convert between FOVs and all other CODs use 0%. Then depending on how the game converts by default, you need to adjust the DPI of your hipfire so that the result of the ADS is the same as you would get if you were converting with Viewspeed v2. This might be hard if you are using 6/11 WPS so if you want to or have to go down this route you may need a lower WPS multiplier.
The next part is to create a macro in your mouse software that allows you to change your DPI when you right click so that your ADS will be the same as your hipfire, based on what you just calculated. However, I'm not too sure you can bind a macro like that with the Synapse software.. the last Razer mouse I used was the Deathadder 2013 and I couldn't find a way so I had to buy a new mouse, but the Chroma might have new features, so can't say for sure.