We will never be plunged into utter confusion. ‘And they need no candle, neither light of the sun, for the Lord God giveth them light.’ That will be literally true in the heavenly Jerusalem.
‘And they shall reign for ever and ever.’ Right now we reign in the sense that, by the help of God, we have self-control. Can we control ourselves, and resist temptation, and do the things we should be doing for the Lord with great happiness and joy and dependence upon him? Do we have dominion wherever he set us, over sin and temptation? But how will we reign in the future glory? That's completely unknown to us, but we will. That eternal city will be vast and beautiful and staggering, may be as big as the universe. Who knows? We can only speak speculatively. That vast eternal realm where we shall have his presence and his power and his love, filling the air all the time. What will we do? We won't have to till the ground; we won't have to do things which are work and toil. But there will be things to be done in the service of the Lord, which will be all joy and fulfilment. We will praise his name, because we will have dominion. ‘Reign’ is mean not in the sense of bossing things around or controlling them, but in the sense of having dominion over God's creation by his blessing, and enjoying happy activities.
Is it wrong to spiritualise the Scriptures? Certainly not when the New Testament uses the same method to interpret the Old Testament for us. The medieval interpreters including Augustine resorted to allegorizing constantly and we feel very uncomfortable with many of their conclusions. They allegorised as a matter of routine in an arbitrary way and especially where they handled a difficult passage from which they could not otherwise easily extract any meaning. The Scripture’s spiritualizing is always based on a God-given connection between two things, as in this case the connection between the first and second creation.