The best hardcore suggestions I could give are Doujins. If we are limited to the Manga tab then I'd say Takeda's
Ima Real, both of Shindo L's books, and both of Aiue Oka's books. Across the five you'll find forced, mind control, drugs, domination, bondage, cheating, NTR, and more. These books are not for vanilla fans. My recommendations for only the truest of cultured weebs.