BTW, the “begats” (the beginning of Matthew) trace Jesus’s family tree — according to JOSEPH’S lineage, not Mary’s. But if he’s only Mary’s son and not Joseph’s, then that lineage is irrelevant and the point it’s making is moot.
Mary came from the same lineage as Joseph, Jesus was equally the hereditary King of the Jews from his mother’s side — as well as from Joseph, who was married to his mother which made Jesus his legal son and heir. He was true royalty, the rightful King of the Jews, although at that time there was no Jewish monarchy, and Israel was a province of Rome.
To a Christian it is very relevant. In fact it is a point of great comfort since a Christian is born from above on a reality plane not readily visible to the eye but nevertheless very real, albeit the outworking of such may take years to be seen in evidence. Joseph gave his name and parenthood to Jesus. Joseph raise the babe up in the Way that He should go, on the human plane.The process of being born from above is analogous to the adoption Joseph offered to the Child. In that regard, Jesus was Joseph's son also, by adoption, just as a Christian is a child of God by adoption and God extending His family name and honor to that born-from-above new creation.
Too often, we are mired in too strict a framework, like accepting ONLY the DNA understanding we have today as the ultimate knowledge of 'how it's done'. But of course we have not a clue how DNA would account for the non-physical 'virtual reality' of the soul and spirit.