Being given cities simply refers to they will be given authority over other believers who were not worthy of ruling. And I do think in the New earth to come, there will be lots of people and people will be given things to do. Scripture mentions judging the nations, well the people are some from every tribe tongue nation that are saved. It will not be a fully egalitarian society. God is not a communist, God rewards some with greater rewards, some with fewer, and some are scarcely saved losing all rewards they might have gotten. Some will have great gains, some will suffer great loss at the judgment.
Some day we will find out who is rewarded with what.
1 Cor 3
9 For we are God’s fellow workers; you are God’s field,
you are God’s building. 10 According to the grace of God which was given to me, as a wise master builder I have laid the foundation, and another builds on it. But let each one take heed how he builds on it. 11 For no other foundation can anyone lay than that which is laid, which is Jesus Christ.
12 Now if anyone builds on this foundation
with gold, silver, precious stones, wood, hay, straw, 13 each one’s work will become clear; for the Day will declare it, because it will be revealed by fire; and the fire will test each one’s work, of what sort it is. 14 If anyone’s work which he has built on
it endures, he will receive a reward.
15 If anyone’s work is burned, he will suffer loss; but he himself will be saved, yet so as through fire.
And the loss is set for eternity.
Daniel 12
And many of those who sleep in the dust of the earth shall awake,
Some to everlasting life,
Some to shame
and everlasting [
a]contempt.
3 Those who are wise shall shine
Like the brightness of the firmament,
And those who turn many to righteousness
Like the stars forever and ever.
8 Although I heard, I did not understand. Then I said, “My lord, what
shall be the end of these
things?”
9 And he said, “Go
your way, Daniel, for the words
are closed up and sealed till the time of the end. 10 Many shall be purified, made white, and refined, but the wicked shall do wickedly; and none of the wicked shall understand, but the wise shall understand.
11 “And from the time
that the daily
sacrifice is taken away, and the abomination of desolation is set up,
there shall be one thousand two hundred and ninety days. 12 Blessed
is he who waits, and comes to the one thousand three hundred and thirty-five days.
13 “But you, go
your way till the end; for you shall rest, and will arise to your inheritance at the end of the days.”