I recently played a (mostly) pacifist V on hard mode. I say mostly because some story missions (e.g. DLC ending choices) force you to kill. I have to say, it ramped up the difficulty in two ways.
First, the gameplay. You truly have to go full netrunner and stealth to make things easier. You have to get creative in completing contractss too. I love that CDPR actually gives us a chance for that though.
Second, and most difficult, the "pacifist" V. I know some are not avoidable, but a non-lethal approach to the story is wildly difficult.
Personally, there are many characters that do not deserve a second chance… but I believe that is the challenge. I allowed myself to play with two freebies. Meaning that either Fingers, Woodman, or other horrible people in the story gets an exemption to the non-lethal rule. Your pick. But after those two exemptions are exhausted, you have to do your best, mentally and gampley-wise to remain non-lethal.
Now for th story behind my V with this one it was a street kid that has seen the horrors of Night City spread deep enough and choose to challenge the city when it presented those choices. And to be fair the approach also helped in some moral high ground moments, which felt rewarding but I don't think I'll ever play with that approach again.
Anyways, I'd love to hear your thoughts! It is soooo difficult of a run.
TL;DR: playing a "non-lethal" V made the game extra challenging in both gameplay and story, especially going against MY personal gut feeling