The concept of “Christian Hell” that you mention is entirely foreign to Orthodox theology. I’ve heard this view from many Protestants, but this is the first time I’ve heard Catholics support it.
Since God is everywhere and fills all things, there is no place that He is not. It is impossible to be separated from God. Your very existence, both now and for eternity, depend entirely upon Him. God is Love, so there is no place or reality that is absent from that Love. How an individual experiences that Love, however, is what determines Heaven and Hell. For those who have sought communion with God during their lifetime, followed His commandments, and who partake in the Sacraments, Heaven is a place of an eternal movement of Love between God and the person, and an eternity of worshiping God’s glory. Hell is a place where that Love is experienced as a burning (“lake of fire”), since the person was not refined during their lifetime and rejected God. The agony for them is not that they want God and can’t have Him, it’s that they don’t want God and continue to reject Him, but are ever-present before His Holiness and Love. Heaven and Hell can both start during this lifetime. Those that reject God and fall into existential despair truly are in Hell, while those that seek communion with Him in the Church are in Heaven. In this sense, Orthodoxy does not believe in an “afterlife”, since one’s soul is immortal; spiritual realities begin during their physical lifetime and extend into eternity.
Purgatory is now, during this physical lifetime, a time of choice and the ability to be purified through repentance and the Sacraments. There is no such state after physical death. It’s a mystery about exactly what happens when someone’s body dies, but we know that they have a foretaste of Heaven or Hell, depending on their acceptance or rejection of God’s Love.