What will New Earth, New Heavens and New Jerusalem really be like according to Catholicism?

The best Catholic commentary on St. John's Apocalypse, Fr. Herman Kramer's The Book of Destiny, says this about Apoc. 21:1-2:

Verse 1

The prediction voiced at the blowing of the seventh trumpet (XI. 15) has at last become actuality: "the kingdom of this world is become our Lord's and His Christ's". A new heaven and a new earth appear. The promise of a new heaven and a new earth was not new in the New Testament; it had been enunciated in the Old. Isaias wrote: "For behold I create new heavens and a new earth: and the former things shall not be in remembrance, and they shall not come upon the heart" (Is. LXV. 17). To this is added the promise of the conversion and restoration of the Jews: "For as the new heavens and the new earth, which I shall make to stand before me, saith the Lord: so shall your seed stand and your name" (Is. LXVI. 22). St. John obviously had the text of Isaias in mind, for his own is verbally almost identical with it. Exegetes interpret this passage in Isaias to mean the happy state of the faithful under the dispensation of the Messias, for they shall be free from the dangers and anxieties of former times, and those who wish to live a Godly life in the world shall find no hindrance to their desires. Since the text is so nearly identical with that of Isaias, St. John surely expresses a fulfillment of the prophecy. By restating it so closely, he applies it to the new state of the world after Antichrist. Isaias, moreover, states that this new heaven and new earth means the changed condition of all things during the millennium (LXVI. 20-23). After the conversion of the heathens, who were ritually impure, and of the obstinate Jews, the Church shall be further embellished by the elevation of the Jews to the priestly dignity and the office of advocates between God and man. Their nation made the coming of the Messias possible; after they are all converted, they shall reap the delectable fruits of that distinction. Thus, after Elias has purified the Church of all hypocrisy, she shall stand in imperishable beauty before the Lord. The new EARTH is the changed state of society, which before and during the days of Antichrist was antichristian and anti-God. It is now entirely submissive to Christ and willing to have all relatons of man regulated and directed by the Church.

The antagonism against the Church is no more. Hence the "sea" has vanished. This "sea" produced all evil in the world. The Church was herself purified and perfected, as far as this is possible on earth, and now this new heaven will radiate benedictions everywhere. The dogmas and moral law of the Church shall suffer no change, but the evils within her at times: the worldliness, lack of fervor, hypocrisy, scheming for control instead of faithfulness to duty, lack of adherence to principle, and above all — lukewarmness in people and clergy — these evils shall be expurgated from the Church in the supreme struggle.

The true spiritual Israel comes forth transformed from the judgment under Antichrist; and transfused with grace it is united in one brotherhood with the remnants of converted heathen nations and stands before the Lord as did the first converts in VII. 9. The NEW HEAVEN is the Church after the conflict with Antichrist mature and transfigured with grace and adorned with all virtues the triumphal achievement of the Lamb. In her earthly form, she reflects the image of the Triumphant Church in Heaven: divine beauty, holiness, immutability, infallibility and indefectibility; and pervaded by the Spirit of God she bears the pledge and germs of divine glory and yearns with inexpressible longing for the pouring out of the messianic benedictions upon all flesh and for the transfiguration and ineffable bliss of the elect in the life beyond.

Verse 2

As the new heaven is the purer survival of the old, and the new earth arises out of the wreckage and decay of the old: So The New Jerusalem is created to be the metropolis of the new earth. The Church cannot exist on earth without a local center, and this will be established at Jerusalem, since Rome is a heap of Ruins and shall never be rebuilt. The Jerusalem of the Old Covenant has been in ruins since the war of Titus, and this fact must have set the Christian mind a-questioning, even in St. John's time, whether and when a new Jerusalem would arise. This new Jerusalem would be of another order and would be the fulfillment of Christian hopes expressed by St. Paul in several letters (Gal. IV. 26). The Apostle clearly designates it to be the Jerusalem of the Gentiles as well as of the Jews. His prophecy has been fulfilled in a spiritual way since the change of pagan into Christian Rome, which has become the Holy City of the New Testament as Jerusalem had been of the Old. Jewish tradition and literature looked for an ideal, a new and greater Jerusalem. They understood this in an earthly sense only, and it remained an indetermined hope until the apostles defined it in a spiritual sense. Yet Jewish traditions were based on the prophecies. When the Church shall establish headquarters at Jerusalem, the prophecies will have literal fulfillment, the blessed visions of peace become true and Jerusalem becomes the Celestial City (Isa. LXVI. 20; LXV. 19; LXII. 6-7; IX. 13-14, etc.). Most modern interpreters have discarded a literal fulfillment of the prophecies of a greater city to be built on the site of ancient Jerusalem and of the Church making this her metropolis. Yet why should not this be contained in the scope of the prophecies along with the spiritual sense?

The New Jerusalem coming from God may be called into existence by Almighty Power, as the prophets intimate, or the city may be rebuilt for earthly purposes and made glorious by the Church. If the Church rebuilt Christian Jerusalem as she rebuilt Christian Rome, it would literally come "out of heaven". Since the Church derives her divine life from the eucharistic Lamb and the indwelling of the Holy Spirit, whatever city she should select for her headquarters or build to suit her needs would come forth from God and would be the Holy City coming down from heaven and elevated to the place of glory intended in the divine plans. The New Jerusalem thus becomes identified with the Church. (Gal. IV. 26).

The sciences have been developed and been proven to harmonize with divine revelation and to call for a Supreme Cause, God, as the origin and end of creation. The true principles of education have been accepted from the Church, because all educational systems that varied with the principles of the Church have to the extent in which they differed been proven failures. Art has been made the servant of truth and morality. Theology has been perfected and philosophy been made to serve theology. Medical science has been transfused with charity. The true and just relation of Labor and Capital and the rights of each have been proclaimed. The moral laws of the Church have leavened all governments to aim at justice for all and privileges for none. All civil laws are tested by the revealed law and interpreted to conform with it. The source of all contentment and felicity in the world is admitted to be a virtuous life, which receives its inspiration and strength from the eucharistic Lamb. And finally the Church possesses the principles long ago clearly taught that shall insure lasting peace on earth between nations. The Church is worthy to be the Queen of the Lamb and with Him graciously to rule the nations of the world. And she shall people heaven with the souls she begets and rears for Christ, the "Father of the world to come". She is thus prepared for the Great Consummation.

The last paragraph here answers your question about "human creations like technology etc."