“Nearly empty” I suppose would be relative to how many are in Heaven. It is doctrine that there is a vast host of demons in hell, and they share a rational nature the same as we do, in being freely able to love God.
St Aquinas differentiates between two different kinds of “wanting”.
Nobody wants to suffer. If they did, it wouldn’t - by definition - be suffering anymore. What those in hell are remorseful about is not what they have done, or what they continue to do, but the fact that there are consequences for it. i.e. it is the difference between being sorry, and being sorry that you were caught, which is as big of a difference as east is from west. Everybody in hell will be sorry, but nonetheless, none of them will love God or ever love God. Their obstinacy is ongoing and eternal, which is the reason Hell is ongoing and eternal. The consequences are always measured & proportional and never more. Temporal punishment for temporal sin. Eternal punishment for eternal sin. If their obstinacy stopped, then hell would stop. But it will never stop.
In private revelation, the suffering of the damned would be increased in the direct presence of God, and in the distant place of hell it is decreased (but compared to earthly suffering, it is unimaginable).