How was it that Jesus was a son of David when Joseph was not his biological father?

[TonyChanYT]

Luke supplied a genealogy bottom-up, Luke 3:

23 Now Jesus himself was about thirty years old when he began his ministry. He was the son, so it was thought, of Joseph,

Jesus was not a biological son of Joseph but a biological son of Mary.

31 the son of Melea, the son of Menna, the son of Mattatha, the son of Nathan, the son of David

According to this genealogy, Jesus was a biological descendant of David through Nathan and Mary. How was Jesus of the line of David if Mary was a virgin?

Now, Matthew provided a top-down genealogy, Matthew 1

1 This is the genealogy of Jesus the Messiah the son of David, the son of Abraham ...
6 and Jesse the father of King David. David was the father of Solomon, whose mother had been Uriah’s wife, ...
11 Josiah the father of Jeconiah and his brothers at the time of the exile to Babylon. 12 After the exile to Babylon: Jeconiah was the father of Shealtiel, Shealtiel the father of Zerubbabel,

This Jeconiah or Coniah was cursed in Jeremiah 22:28-30. His physical descendants would not sit on the throne of David. To get around this curse, Joseph was not the biological son of Jesus. He adopted him.

16 and Jacob the father of Joseph, the husband of Mary, and Mary was the mother of Jesus who is called the Messiah.

Now in Luke 1:

26 In the sixth month the angel Gabriel was sent from God to a city of Galilee named Nazareth, 27to a virgin betrothed to a man whose name was Joseph, of the house of David. And the virgin’s name was Mary.

Joseph was a biological descendant of David and Jeconiah. The biological descendant of Jeconiah could not be king.

32 He [Jesus] will be great and will be called the Son of the Most High. And the Lord God will give to him the throne of his father David,

Gabriel affirmed that Jesus was a son of King David. From Joseph's side, Jesus was not a biological son but an adopted son. As such, it was possible for Jesus to be king.

33 and he will reign over the house of Jacob forever, and of his kingdom there will be no end.”

It was the kingdom of God.

Let propositionn P1 = Jesus was a son of David.

Is P1 true?

According to human logical reasoning, there are some weaknesses in affirming P1 on either Joseph's side or on Mary's side. However, Gabriel affirmed this. So, overall, judging the pros and cons factors, I accept P1.