The word hiereus IS in fact used of Christian priests, specifically those who would rule with Christ as kings and priests. The word hiereus is used of Christ as he is archiereus not archpresbyteros.
Both Paul and John use the Greek hiereus to speak of these king/priests and the Jewish priests but presbyteros and hiereus are NOT used interchangeably....because presbyteros does not mean priest and the defect is not in the English language but the efforts to do retro-exegesis according to the bias of the Catholic church and its efforts to install priests in the Chistian congregations where none exists.
I see how well you “read Greek in the original” and so forth.
Paul knew the word for priesthood and he didn't use it at 1 Tim. 4:14. Paul used the word prebytery, elders, older men not priests or hiereus.
But you should know this since you “read Greek in the original” and should require no further enlightenment from me.
Yes, -- in Revelation ιερευς is used for the Christian priests, and also in Hebrew the word is used for Christ. I did not say that ιερευς was never used in Christian context, -- Catholic priests have in fact removed the need for the Hebrew priests as they, the Catholic Priests, are priests after Christ (John 20:21) in the order of Melchisedech, -- I said that when the affairs of the Church are described in Pauline letters, a new and specific word is used, πρεσβυτερος to more accurately describe the new function.
install priests in the Chistian congregations where none exists.
No Hebrew ιερει exist in the Christian Church that Christ founded; πρεσβυτεροι very much exist because St. Paul writes of them to Titus and Timothy. They are Catholic Christian priests.