Hades is the remand prison system before Jesus judges everyone for what they have done in this life. Like any prison, it is gloomy and miserable, a difficult life, missing what we had before. Hades is below the earth, like a dungeon system.
Jesus spoke of one very rich and very callous man in Hades desperately hot, tormented. Hades is, mostly, under the control of the devil, with unclean spirit-guards working for him. The torment comes from the heat and from the guards, making people feel like scum with no hope. Jesus spoke of the outer darkness where there is weeping, wailing and gnashing of teeth. A horrible place we don’t want to be in even for half an hour.
Jesus also spoke of Abraham and a poor beggar in another, separate, part of Hades which was more comfortable, which had cool water. We can understand this as the inner darkness, gloomy and restricted but more bearable.
Jesus has been into Hades, between dying and walking out of his own tomb. He said he now has the keys of Hades. He can go in and out whenever he wants, with whoever he wants. Hades is open to Jesus.
Hades is also open to people in Paradise. Jesus said the gates of Hades will not be able to stop the people who live with him and follow him. They too will be able to go in and out whenever they want, with whoever they want.
In Revelation John wrote of angels with Jesus also present in Hades. Hades is not beyond the care and love and forgiveness of God for anyone who wants forgiveness and a better future.