Live a Live’s Twilight of Edo Japan chapter gives a special completion reward if you complete it with zero kills, or a full 100 kills. It’s designed in such a way that figuring out how to do the pacifist run is a puzzle you are unlikely to solve on your first playthrough.
This mechanic was actually one of the inspirations for Undertale!
It is in the original. For the most part, 2022 is very faithful to the original and doesn’t feature any big structural changes (apart from one new thing that’s a big spoiler), mostly just balance and quality of life improvements.
Like I said, Toby Fox openly cited this segment as an inspiration for Undertale (2015), and that came before the 2022 remake.