We are spiritually dead, alienated from God as a non believer.
That’s right, but that‘s a metaphorical application of death. We might say that they are, to use a figure of speech, “dead men walking.” They have no future unless they repent. They will literally be cut off from God.
Are they literally cut off from God now? I don’t think so. God still cares for them, whether they acknowledge him or not.
David asked where he could go to escape from God’s presence (Psalm 139:7). As long as David exists, he cannot escape God’s presence. The same is true with us.
That brings us to the place of final destruction of the wicked: the lake of fire. The second death.
Once they are destroyed they cease to exist forever. There is no greater separation from God. They are no longer in his care. God will have put them finally and forever out of their misery, having dealt justly and compassionately with them.
Alternatively, once they are destroyed (consciously tortured in fire and with immortal worms gnawing at them but not consuming them) if they continue to exist then they are not separated from God‘s presence. They are still in his care - and his care is no longer benevolent, to put it mildly.
Does the punishment fit the crime?
Will God preside over these wicked (and now miserable beyond imagination) people forever?
Can you picture God patiently dealing with them during their natural lifetime? Easily, I would think. He wants all men to repent, turn to him, and be saved.
Can you picture God tormenting them endlessly when they don't? I don’t know about you but I don’t see that as being compatible with God’s character. It reminds me, though it pales in comparison, of the character of the worst tyrants in the history of mankind.
Do you have family, friends and acquaintances who died unsaved? I do.
God will have them consciously tormented without respite? For a week, a month, a year, a thousand years, a million years, a billion years, a trillion years? That’s not even a drop in the bucket of eternity.
That’s also not the God whom I see in scripture.