Regarding 10 nullifiers and obligation to hate sin in heart (was told Ibn Taymiyyah said not hating the sin is kufr), please explain difference between loving sin or thinking sin (smoking, Zina, etc) is cool verses kufr? When sinning I dont really hate it and might love/admire it JazakAllahu khairun

Loving a sin out of desire while you know and believe it is haram is a sin and a weakness of iman (faith), but it is not kufr (disbelief). Imam Ibn Baz stated that the sinner who knows it is a sin and is driven by desire and shaytan is not a kafir unless he deems the sin lawful. Kufr enters when a person makes the haram halal, or hates the ruling Allah revealed, or loves the sin out of hatred for the law of Allah.