According to the most zealous Christians and the Bible, the only way to get into Heaven is to accept Christ into your heart, so he will take the hit for all your sins. Additionally, the Bible also says that Heaven is praising God for eternity, and that the Angels and God are more like eldritch abominations then benevolent beings.
So, perhaps it could be revealed that not only will Heaven not accept anyone from Hell, but that Heaven is also worse then Hell, since you have no freedom. So it's possible that the Hotel will shift it's goals a bit. Redeeming demons is still a priority, but it's not to get them to Heaven, it's to make Hell a better afterlife, one that celebrates the fact that no one is perfect, and marvels at imperfection.
One where you can make your own choices, where if you're too bad by Charlie's standards, the Hotel is ripe for you. And Hell decided to start resisting the purges, and start fighting back until Heaven acknowledges it as a free afterlife.
But this won't be easy, as it means changing the standards that Hell pushes for, and unless Lucifer's love for his daughter is able to overshadow his dark side, Lucifer may have to become a villain and be killed off, so Charlie can become Queen.