I'm mostly looking for demonic cultivation where the MC is not necessarily evil or anything. I'd be interesting if it took a more pragmatic view of demonic cultivation, like "Hey, it's just another path towards the Dao" and all that. Besides, while I like Harem, it truly reaches a ludicrous level in Grasping Evil.
For the first point Grasping Evil fits the bill. I wouldn't call Ning Fan strictly evil, to him demonic dao is just a path, or at least that's how he grows to see it after maturing a bit. One of his love interests is even a righteous path cultivator and he doesn't try to force her to discard her identity/ideology or anything like that. As for harem it's fairly big sure, but the author does a good job of managing it without any annoying drama or girls flocking around MC left and right 24/7. There are a lot of interesting love interests as well imo.
Wang Lin, Su Ming, Meng Hao. They're want to become Immortal/Celestial but their journey lead them to different path, all of them practice some demonic cultivation