As I menrioned, I only Speedrun the NTR stuff, so my knowledge there is limited, it seems cheating is the only option available to you at that point.I am on hardcore, the options that are locked out to me is being Jamal's gf and the one that is available is being Jamal's friend with benefits.
As I wrote in the earlier post, at the beach for Mei to be able to become also Jamal´s girlfriend (they form a threesome/throuple then) you need to be on sharing, being on good terms with Jamal, you and wife being in love (6 or better more love points) and having shared with Jamal before (needs some few rival points easily gotten).
Friends with benefits also needs you and Jamal on good terms, MC and wife in love (not as much so you can optionally develop towards cucking and darker stuff, but I personally play with high love points here as well) and a couple rival points (you should get enough simply with the Halloween event).
For these options you enable both NTR and Sharing at gamestart, no hardcore mode. It seems to me that hardcore mode enables only the darker paths, heavy cheating, going behind the back, aggression and stuff. For FwB or even a real boy/girlfriend relationship you need to be a modicum of a decent person, all characters on hardcore from the MC to the last NPC are decidedly NOT nice persons.
Hope this helps you a bit.