Nebuchadnezzar was called King of Kings, fact not assumption. Jesus Christ is called King of Kings, fact not assumption. Mary is Queen of Heaven, fact not assumption.
The significance of Mary Queen of heaven can be found in Scripture, but only if you understand the significance of the person Mary and Jesus Christ. These two are very special species of man. Mary, created immaculate in the womb of her mother never knew sin. Her birth is the promise and the hope that we too will become like her, a New Eve. The salvation she received through Christ is the very salvation we hope to receive, re-capturing a semblance original justice; or if you please the removal of original sin. This is only done perfectly in the Baptismal founts of the Catholic Church. After receiving this grace, it becomes ours to keep and to exercise in the discipline of faith.
Mary is called Queen of Heaven because of her relationship with her Son; simply her son is the recipient of the Kingdom on earth and the Kingdom in heaven. Her relationship is identical to Bathsheba's relationship the inheritor of David's Kingdom Solomon. Solomon could not deny his queen mother any favor she asked of him as she sat on the throne at his right side. [Cf. 3 Kings 2:17-25] As Solomon is David's son inheriting the throne, so too is Jesus Christ the Son of David. God sends Gabriel who first addresses her has being exceeding blessed 'full of grace', blessed among women. But then Gabriel tell this child she will give a virgin birth to a the Male heir of the throne of David, 'His father, and will reign over the house of Jacob for ever – in case you don't know that's a long time to come. Christ is King of His Kingdom on earth, the Catholic Church, and His Kingdom in Heaven. Mary is the queen of both those Kingdoms and sits at His right side just as Bathsheba, David's spouse sat at the right hand of her son. David the King forsaw things to come writing the psalm:
A canticle for the Beloved. . .Thy throne, O God, is forever and ever: the sceptre of thy kingdom is a sceptre of uprightness. Thou hast loved justice, and hated iniquity: therefore God, thy God, hath anointed thee with the oil of gladness above thy fellows. Myrrh and stacte and cassia perfume thy garments, from the ivory houses: out of which the daughters of kings have delighted thee in thy glory. The queen stood on thy right hand, in gilded clothing; surrounded with variety.
Hearken, O daughter, and see, and incline thy ear: and forget thy people and thy father's house. And the king shall greatly desire thy beauty; for he is the Lord thy God, and him they shall adore. (Psalm 45:7-11)
She is the only human that I know of as
kecharitomene, “most favored or highly favored”; a verb describing something that happened to a noun, in the past tense (past perfect participle of charitoo) and continues until this day. The 'perfect' action of the participle is considered to have been completed before the time of the speaker and having an effect today and will continue in the future. Hence when we could translate the phrase “Hail, Mary full of grace” to highly favored in the present we would need to add, “Always”. The Salvific grace was given to Mary prior to the annunciation remains at the annunciation and its radiance remains to this very day today.
No assumption on my part, do you want to revisit your part?
JoeT