How does a gun get more recoil when properly shouldered ?
It’s a constant. You shoot, you get a X value amount of recoil.
How you shoot it changes how much control you exert over that force resulting from the recoil.
Shouldering the gun allows to use your body to counteract that force.
I also do not see any game with worse recoil when shouldering your gun. This simply does not work like that in real life or in games.
ADS has precision at the expense of time consumed to fire and finely aim your gun.
There is no increase in recoil (a constant from the gun/ammo combination itself) but better control of recoil when you use your whole body as a support shouldering it.