Hell already exists it’s a place where the wicked dead go to wait for judgement and eternal Damnation , hell will cast into the lake of fire with Satan , his servants and angels and all who reject the gospel
hell is a spiritual place for the spirit of mankind to await thier deeds who were wicked whereas paradise awaits those who repent and believe such as the thief on the cross when they pass through this world
man has a spirit and a body the body dies and returns to the earth the spirit returns to God for judgement. The wicked await damnation the believers who repented await the restoration of all things when Christ returns
hell is now a spiritual prison of sorts for the wicked because man has a spirit and spirit doesn’t die the body dies , spirit endures there is an afterlife that consists of heaven and hell now . They are spiritual realms unseen by us until we shed the flesh and see in full
the gospel is about after this lifetime for the most part we learn how to live in peace here but our promises are all for after we part from our body