Is owning an apartment that was nationalized by the state, after it was given to me by my father who bought it from someone who did not have clear ownership of it, permissible (halal), especially if I don't take it, one of the officials will?

If someone finds unlawfully acquired money and neither the owner is known nor can be ascertained, then they may spend it on themselves and their families if they are in need, because the way to deal with ill-gotten gains is to give them away in charity, and it is permissible to spend them on one's own needs. As for this apartment, if you are among those entitled to it, then you may own it; otherwise, you should give it to someone who is entitled to it. For this reason, it is permissible for impoverished heirs to take unlawful money from an inheritance, whose owner is unknown, as a charity on behalf of its owner.