Has anyone ever tried the devil/cursed/corruption/sacrifice other people for power path
I have yeah, and for all intents and purposes. Its called the Demonic Cultivation Route
If yes, then what are it's impact on story
As of right now, there are none. Do not, however, mistake this for thinking there won't be any. There will be, anything beyond that would be a spoiler.
Does talks with bald clone guy goes differently or not
Taio the Bandit & Taio the Scholar, there won't be any unique interactions with them initially, since you aren't on the path till after you kill them both.
They will, however, become your mentors in Demonic Cultivation. The mechanics of it I won't exactly spoil, since they are both pretty funny and you should experience it for yourself firsthand during Chapter 8.
Has anyone recognised that you practice dark arts
As of right now and among the cast we've already met, only Angelo knows your playing for the other team.
Kosuke might suspect it, especially if you did the sacrifice in Chapter 2 but she/he doesn't know for sure.
Later on however, certain characters will find out.
Tbh it would be interesting to see how people close to mc would react to the revelation
Interesting is certainly one word for it. All I will say is, you disappoint Mother and Father is getting the belt.
Personally haven't tried that route
I'd give is a shot honestly, I know I'm ragging it slightly. And for good reason mind you but it is nicely written and it does indeed have some gains for the short-term. I'd just not make it my canon MC's path.