Are you starting at season 2? I recommend starting with from the beginning, which means that the kinks get enabled naturally (don't worry if you loose them because a particular scene doesn't appeal to you). The codes give a bit extra content, but don't change the narrative.
As for harem, that is complicated as people have different definitions. You can pursue any woman with pretty much no drawback jealousy. They may be in relationships or have past relationship, which they will tell you about when asked. Some are aggressive and domiant, you must avoid and flee from them if femdom is a big problem for you. There are diffent alien, demon and synth women. You can choose them individually, you don't need to enable all. The game features the option to enable "Silverback" a bit into the game which means that all MF scene without the MC are blocked. Lastly, a lot of nudity is unavoidable, so be warned if male nudes are a big problem for you.