It is heresy to follow Core and assert that there is no need for a priesthood.
It is heresy to deny words directly from the mouth of Christ Himself.
It is heresy to deny that Christ Himself founded a visible Church to be a light on a hill, not something invisible and therefore much worse than a candle under a bushel basket.
have a nice day
Nobody is denying our Lord Christ Jesus.
Scripture is used to communicate the Word of God, which is then used by God the Holy Spirit to sanctify the believer.
Jesus Christ never authorized the Apocrypha, nor were they given in the Hebrew Canon, nor were they considered a part of the Canon by earlier Catholic Councils. They were not written by Prophets, so they are not the Word of God. If one were to be consistent, then a countercharge could be leveled that anybody adding the Apochypha to Scripture is heretical.
As believers through faith in Christ we all are part of His Royal Priesthood. It is heretical to imply believers are not part of that Royal Family.