Hebrews 5:6 “You are a priest forever according to the order of Melchizedek”;

I’ve studied on this verse for many years since first reading it.
Have you ever wondered how Jesus is a priest also?
The priestly tribe are the Levites, descendant from Aaron, but Jesus is a descendant of David and is from Judah, which is the lineage of the kings.
This in not a New Testament verse but comes from Psalm 110. So it’s something David prophetically penned.
Melchizedek is found in Genesis 14:18, where he just appears out of no where.
Many believe this is a pre-incarnation of Christ but I don’t.
I believe he is Shem, the son of Noah, from whom the Hebrew lineage and Abraham descends.
In fact, Shem is Abraham’s great, great, great, great, great, great, great, grandfather.
If true and Shem and Melchizedek are the same, it explains some things in a later chapter of Hebrews.
Shem/Melchizedek is a priest before priests. The tribe of Levi is still bound up in Abraham, who is yet to have a son when they meet.
So Melchizedek was a priest, not by birthright, but by choice.
Jesus became our perfect, sinless High Priest by choice and did not offer the blood of bulls or goats but His own innocent blood and a more excellent sacrifice for us.