Your frustration is understandable haha, the guns are really annoying, especially once you move into harder areas where it's nearly a one shot kill. Just keep an eye out for the crosshair symbol above their heads, once it turns bright red this means they'll shoot, all you have to do is dodge at this point, or alternatively do everything stealthily.

I will agree that the guns do get rather annoying, however this is to be expected seeing as the game is progressing through time. It is at least reasonable when the enemies are on ground level, but it gets annoying when they are up on higher levels whilst you are fighting on the ground.

This being said, it is generally easy to dodge the shots, just wait half a second after the lock-on marker is lit and proceed to roll away or towards the enemy with the gun. You can then proceed to continue combat and nail countless parries, god only knows they are more important in this game than in previous titles.

Overall, I think they are annoying, but they are manageable.