High Priest (physical/temporal) - High Priest (Spiritual/Eternal)

Colossians 2:13-14

The high priest serves as a mediator between God & the people.

God appointed Aaron as the 1st (physical/temporal) High Priest (Num 17:1-9)

Num 17:8 Now on the next day Moses went into the Tent of the Testimony, and [a]the rod of Aaron of the tribe of Levi had sprouted and put out buds and produced blossoms and yielded [ripe] almonds.
(MY NOTE: Aarons dead wood staff blossomed overnight with stems/branches full of ripe almonds. A foreshadow of resurrection life)

God appointed Jesus (spiritual/eternal) High Priest (Heb 4:14, 5:5)

Heb 5:5 So too Christ did not glorify Himself so as to be made a high priest, but He [was exalted and appointed by the One] who said to Him, “You are My Son, today I have begotten You [declared Your authority and rule over the nations]”
(MY NOTE: Father God appointed Christ high Priest/mediator between God & all within our realm/universe)

Christ's appointment nullifies the old (physical/temporal) Levitical sin management covenant.

Heb 8:
6 But as it is, Christ has acquired a [priestly] ministry which is more excellent [than the old Levitical priestly ministry], for He is the Mediator (Arbiter) of a better covenant [uniting God and man], which has been enacted and rests on better promises.
(MY NOTE: Christ acquired/mediates a more excellent Priestly/sin management ministry)

13 When God speaks of “A new covenant,” He makes the first one obsolete. And whatever is becoming obsolete (out of use, annulled) and growing old is ready to disappear.
(MY NOTE: Christ's new Priestly ministry covenant nullified the old Mosaic/Levitical covenant)

This Christ New Testament/covenant Priestly sin management ministry, forever replaces the old Mosaic/Levitical sin management covenant)

Implementation of a testament/covenant requires a death:

Heb 9:
15 For this reason He is the Mediator and Negotiator of a new covenant [that is, an entirely new agreement uniting God and man], so that those who have been called [by God] may receive [the fulfillment of] the promised eternal inheritance, since a death has taken place [as the payment] which redeems them from the sins committed under the obsolete first covenant.
(MY NOTE: Believers in Christ sin atoning death & resurrection receive an eternal inheritance)

16 For where there is a will and [d]testament involved, the death of the one who made it must be established,
(MY NORE: Christ's death & resurrection is where the new covenant is established)

24 For Christ did not enter into a holy place made with hands, a mere copy of the true one, but [He entered] into heaven itself, now to appear in the very presence of God on our behalf;

28 so Christ, having been offered once and once for all to bear [as a burden] the sins of many, will appear a second time [when he returns to earth], not to deal with sin, but to bring salvation to those who are eagerly and confidently waiting for Him.
(MY NOTE: Christ's perfect sinless once for all time sin offering. Fulfilled the laws required wage/price for sin [Rom 6:23] Jesus conquered & destroyed sins death grip, administered through old covenant law ordinances.)

We seize/access this new sin management covenant by faith [Rom 5:1-2] When we trust in Jesus' sin atoning death [sins required wage PAID] burial [proof Jesus died] & resurrection [Father God's receipt, sins required wage received & accepted - 1 Cor 15:1-4] Amen

Ps 37:28 For the Lord loves justice And does not forsake His saints; They are preserved forever, But the descendants of the wicked shall be cut off.
(MY NOTE: The Lord doesn't forsake His saints/believers but PRESERVES them FOREVER!)

Heb 9:12 Neither by the blood of goats and calves, but by his own blood he entered in once into the holy place, having obtained eternal redemption for us.
(MY NOTE: Christ obtained ETERNAL REDEMPTION for all believers)

Heb 10:14 For by one offering he hath perfected forever them that are sanctified.
(MY NOTE: Christ PERFECTED FOREVER all believers He has sanctified)

Heb 13:20 Now the God of peace, that brought again from the dead our Lord Jesus, that great shepherd of the sheep, through the blood of the everlasting covenant,
(MY NOTE: This new sin management blood covenant is EVERLASTING! Not just 1 year or until the next time to stumble or fall/sin)

Believer's sins are forgiven & washed away via an EVERLASTING COVENANT!

God created the old covenant; God cannot make mistakes. Matthew 5: 48 Be perfect, therefore, as your heavenly Father is perfect. It saved man in sleep; they did not go to heaven until Christ was crucified. Matt 27:50-54 “Jesus, when he had cried again with a loud voice, yielded up the ghost. And, behold, the veil of the temple was rent in twain from the top to the bottom; and the earth did quake, and the rocks rent; And the graves were opened; and many bodies of the saints which slept arose, And came out of the graves after his resurrection, and went into the holy city, and appeared unto many. Now when the centurion, and they that were with him, watching Jesus, saw the earthquake, and those things that were done, they feared greatly, saying, truly this was the Son of God.”

The Old Testament tells of God communicating with man through the flesh. The commandments were of the earth, symbolic of the spirit of God. God’s saving grace through forgiveness was symbolized by the blood of perfect animals, cutting of flesh symbolized spiritual circumcision.

Christ fulfilled all of these symbols. The symbols were not to be used any more, for Christ is the reality.

This is 144,000 related.And all those who God had set aside throughout history.Anyone who wants to study the 144,000/Two Witnesses,study the remnant.When God gave the Levites a everlasting priesthood he kept his promise.It is through the remnant that his promise is delivered.

Numbers 25:10
And the LORD spake unto Moses, saying, Phinehas, the son of Eleazar, the son of Aaron the priest, hath turned my wrath away from the children of Israel, while he was zealous for my sake among them, that I consumed not the children of Israel in my jealousy.Wherefore say, Behold, I give unto him my covenant of peace: And he shall have it, and his seed after him, even the covenant of an everlasting priesthood; because he was zealous for his God, and made an atonement for the children of Israel.

The 144,000 will be from the Order of Melchizedek because they will have the fullness of Christ in them.To the people it will be like seeing Jesus in the flesh.

Leviticus 14:14-18

And the priest shall take some of the blood of the trespass offering, and the priest shall put it upon the tip of the right ear of him that is to be cleansed, and upon the thumb of his right hand, and upon the great toe of his right foot:

And the priest shall take some of the log of oil, and pour it into the palm of his own left hand:

And the priest shall dip his right finger in the oil that is in his left hand, and shall sprinkle of the oil with his finger seven times before the Lord:

And of the rest of the oil that is in his hand shall the priest put upon the tip of the right ear of him that is to be cleansed, and upon the thumb of his right hand, and upon the great toe of his right foot, upon the blood of the trespass offering:

And the remnant of the oil that is in the priest's hand he shall pour upon the head of him that is to be cleansed: and the priest shall make an atonement for him before the Lord.

I've talked about the right side of the body being made in the image of the new covenant.The right ear for spiritual hearing of the word,the right thumb for spiritual works,and the right big toe for your spiritual walk.

When you were at your lowest point in life and God held his hands out to you,how does he do it?through his word,his Covenants.
Face your palms out in front of you.You are looking at two living stone tablets.Place them side by side and you have yourself a Bible.

The remnant/144,000 will make atonement for the people and cleanse them through the word of God.His Two Witnesses of Revelation.
When Jesus died and the temple veil was torn in two,what happen to it?
One side was parted to the left and the other to the right.
If you want to walk past the veil and see the revelation of Jesus Christ,you need to be cleansed by the word of God.The curtain veil is the word of God.Aka the Bible.

I see several problems with your assessment.

1) Under the law all priests had to be descendants from the tribe of Levi.

2) The 144,000 are 12,000 from each tribe.

3) The Num 25:10 promise you cited made to Phinehas (a Levite) continued as long as the Mosaic law was in effect.

4) Jesus was from the tribe of Judah

Christ's (the Lion from the Tribe of Judah Ren 5:5) priesthood is eternal & unchangeable (Heb 5:6, Ps 110:4). Christ's Priesthood doesn't pass from one to another. Christ's sacrifice is perpetual in both efficacy & virtue, in its ability to, not just cover one Nation's sins for 1 yr, but REMOVES ALL sin.

The risen Christ lives eternally to make intercession on behalf all believers from all nations & tongues (Heb 7:21)

Additionally:
A remnant is a portion of something left over from the whole. Remnant is used multiple time throughout OT scripture.

Here are a couple (there are several) NT remnant verses unrelated to the 144k

Rom 11:5 Even so then at this present time also there is a remnant according to the election of grace.

Rom 9:27 Esaias also crieth concerning Israel, Though the number of the children of Israel be as the sand of the sea, a remnant shall be saved:

I adamantly reject the ascertain that the 144,000 are THE remnant. Having said that you're free to believe & promote your heart, as am I. Best wishes, FD.

Believer's sins are forgiven & washed away via an EVERLASTING COVENANT!

Amen! Jesus is the fulfillment of the prophecies and the true image of what the OT priests symbolized.