Full-Time Time Travel: Am I a Painter in the End of the World?

This is a false world built for the dead who are trapped by unfinished obsessions. All people with regrets after death will be transferred here from the earth by priests and become "Grudges". They can inherit the abilities they had during their lifetime. For example, the delivery boy can teleport and keep his belly from being hungry. Although the abilities have no restrictions on their use, they must conform to realistic logic. Outrageous effects such as mobilizing water in the human body are prohibited, and no one can escape on their own once they enter. When each stalker arrives for the first time, he will receive a "god core" cube wrapped in black mist, extremely hard and indestructible. Thegod core can be actively snatched or passively obtained by the enemy. Collecting 9god cores and piecing them together into a large cube is the only way to leave this world, but no one knows whether they will live or die after leaving.