Jerome went further.
One favored by God means God is giving something to the person.
Favor means to bestow favor, not just to “like” someone.
Favor is a verb of doing to someone, used here as an adjective meaning that the noun (Mary) described has been “done something to her”.
What does God have to Give except himself?
Gabriel confirms that God has given himself, he CLARIFIES by explaining what “full of grace” means with the next clause - “the LORD, ‘I AM’, is with you”, meaning the Holy Spirit with infusion of Grace is perpetuated within you.
It is only in the Protestant era when grace began to be seen as a “frame of mind within God” rather than the Universally known understanding of Grace as a real given gift that is now contained within the recipient; it is contained for use in living the virtues joyfully, and singing, “My soul magnifies the LORD!” That cannot be sung as a statement of reality within a person except that a person is full, infused, of Grace.
Thus Jerome had to render it as the Church knew it to be with Mary. Many possible alternatives to linguists, yet only one of them posited by Sacred Tradition.
We are “quoting” Gabriel in our Prayer of the Rosary; we are quoting literally from Luke’s writing; we are not in error in that quotation as if we did not understand Greek.
As to how a person would say “Full of Grace” in Greek, translating the other way around, I thought I might try Google Translate (to modern greek of course).
I entered “Gracefilled woman” in English, and what came out in Greek?.. χαριτωμένη γυναίκα. (Charitomene Gynaika)
Same participle as some translators would nowadays say means, “favored woman”, when the “tradition” of the person who created the original phrase (myself) intended “Gracefillled Woman”.
So, when Luke translated Mary’s Aramaic or Hebrew to Greek, he chose the perfect participle, but same word.
John Martin