Cause the unique and legendary cyberware does not matter at all. Wether you have it or not, use it or not. There is something weird going on with how the game is balanced and how Equipment works in the game (stat boosts). There was some reddit post about a person testing it. I think the most important influence is your lvl and stuff outside of this barely matters.
My V used the eye scanner and the hand cyberware you get from the story mission and nothing else. And i still oneshot every enemy on the hardest difficulty (except bosses, which also died like flies btw).
So yea it does not matter at all.
Edit: story wise it has literally zero impact, and I guess that was the most important impact to me. Gameplay wise see what i said.