If you read Paul letters he also refers to others “ as ministers” of Jesus Christ, not just the 12 apostles.
God’s ministers and priesthood started long ago, well before the 12 apostles. And this priesthood continues even today in those whom God has chosen and anointed to minister to, and for Him, every man in his course.
God is gathering for Himself a nation of Kings and priests to reign with Him.
Exodus 19:6
And ye shall be unto me a kingdom of priests, and an holy nation. These are the words which thou shalt speak unto the children of Israel.
Revelation 5:10
And hast made us unto our God kings and priests: and we shall reign on the earth.
Peter calls Gods elect a “holy priesthood”…
“Ye also, as lively stones, are built up a spiritual house, an “holy priesthood,” to offer up spiritual sacrifices, acceptable to God by Jesus Christ.”
Peter also calls us a royal priesthood…
9 But ye are a chosen generation, a “royal priesthood,” an holy nation, a peculiar people; that ye should shew forth the praises of him who hath called you out of darkness into his marvellous light;”
We are called “ministers” “oracles” and also “stewards”…
1 Peter 4:10-11
King James Version
10 As “every man” hath received the gift, even so minister the same one to another, as good stewards of the manifold grace of God.
11 If any man speak, let him speak as the oracles of God; if any man minister, let him do it as of the ability which God giveth: that God in all things may be glorified through Jesus Christ, to whom be praise and dominion for ever and ever. Amen.”