Doesn't Jesus' office, of our High Priest, after the order of Melchisedec, last forever?

Hebrews 8:7 For if that first covenant had been faultless, then should no place have been sought for the second.

  13 In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.

Hebrews 7:11 If therefore perfection were by the Levitical priesthood, (for under it the people received the law,) what further need was there that another priest should rise after the order of Melchisedec, and not be called after the order of Aaron?

  12 For the priesthood being changed, there is made of necessity a change also of the law.

So, did not the priesthood change from the order of Aaron, under the first covenant,

to the order of Melchisedec under the new covenant?

Hebrews 3:1 Wherefore, holy brethren, partakers of the heavenly calling, consider the Apostle and High Priest of our profession, Christ Jesus;

Hebrews 5:6 As he saith also in another place, Thou art a priest for ever after the order of Melchisedec.

Hebrews 6:20 Whither the forerunner is for us entered, even Jesus, made an high priest for ever after the order of Melchisedec.

Hebrews 7:17 For he testifieth, Thou art a priest for ever after the order of Melchisedec.

  21 (For those priests were made without an oath; but this with an oath by him that said unto him, The Lord sware and will not repent, Thou art a priest for ever after the order of Melchisedec:)

  24 But this man, because he continueth ever, hath an unchangeable priesthood.

So, why would some insist that the priesthood change back to the order of Aaron?

How could animal sacrifices, in a tribulation temple, possibly be acceptable to the LORD,

while those priests still reject the perfect blood sacrifice of the Lamb of God?

Also, I was always taught that Ezekiel 40-48 describe a reinstated Aaronic priesthood making sin offerings in the kingdom.

But how could that be?

They told me that the millennial temple sacrifices will be in remembrance of the cross.

However, the words, memorial, remember, and remembrance are not used in Ezekiel 40-48.

Is it possible, that what is described in Ezekiel 40-48, about the sacrifices done by the Aaronic priest, the sons of Zadok,

is what the future kingdom would have been like under the first covenant?

But now that there is the new covenant in the blood of Jesus, that not only were the sacrifices of Exodus through Deuteronomy,

have all been completely fulfilled by the cross,

but that also that the cross has already completely fulfilled the sacrifices of Ezekiel 40-48?

So that there is no more need for the sacrifices in Exodus through Deuteronomy,

and that there is no more need for the sacrifices of Ezekiel 40-48?

Wouldn't it be similar to how the catholic mass is like "re-crucifying" Jesus each mass?

Also:

Hebrews 10:17 And their sins and iniquities will I remember no more.

but:

Hebrews 10:3 But in those sacrifices there is a remembrance again made of sins every year.

Is it possible that in the millennial temple, that Jesus may do like he did on the road to Emmaus, after his resurrection?

Luke 24:27 And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself.

But maybe much more detail, and progressively deeper as time goes on?