I went back and got the best ending for the Sofia route!
It didn't require nearly as many horrible things as I expected. I made some pretty significant mistakes in my first run, and simply fixing them was enough to bring me very close to victory. There was one choice that hurt, because I almost certainly could have won without compromising my ethics. But when I thought about it, would my character have been willing to take that chance? Would I want to sacrifice my happiness, and the happiness of the people I love, for a stranger?
It was not pleasant, but I don't regret my decision. And while the Sofia route could be difficult and painful at times, that only made the ending more satisfying. Thank you!