I've only provided evidence in the OP that confirms Joseph, Simon, James, and Judas in Matt. 13:55/Mk. 6:3 were Jesus's brothers, and shows that the type of brothers all four men were to Jesus were kin, specifically His cousins, not siblings as you believe.
In my previous post, I addressed your claim that Scripture "plainly states" in Matt. 1:25 that Joseph and Mary didn't have intercourse and more children until after Mary gave birth to Jesus, but it doesn't; rather, it states they didn't have intercourse "until she brought forth her firstborn son." The word "until" has multiple meanings, not only the one you're inferring by your insertion of the word "after." For the sake of argument, say the word "until" was used to mean Joseph and Mary had intercourse after Jesus's birth, that in itself wouldn't mean Mary bore more children because, for example, having vaginal intercourse doesn't lead to procreation for some men and women. Your interpretation that the gospel writer, after writing about the long-anticipated messianic prophecy coming to fruition, basically threw in the tidbit, "After the birth of the Savior, Joseph had intercourse with Mary and 6+ more kids," at the end is quite random. It also isn't in line with the context of Matt. 1:20-25:
"But while he thought on these things, behold, the angel of the Lord appeared to him in his sleep, saying: Joseph, son of David, fear not to take unto thee Mary thy wife, for that which is conceived in her is of the Holy Ghost. And she shall bring forth a son, and thou shalt call his name Jesus. For he shall save his people from their sins. Now all this was done that it might be fulfilled that which the Lord spoke by the prophet, saying: Behold, a virgin shall be with child and bring forth a son, and they shall call his name Emmanuel, which being interpreted is, God with us. And Joseph, rising up from sleep, did as the angel of the Lord had commanded him, and took to him his wife. And he knew her not until she brought forth her firstborn son, and he called his name Jesus."
The context of Matt. 1:25 is Joseph's accepting as his spouse the virgin who conceived the Savior of mankind by the Holy Spirit. The gospel writer concludes the passage by stating that Joseph didn't have intercourse with Mary until Jesus's birth, to dispel any belief that he was the father. Therefore, the meaning of the word "until" that applies in "And he knew her not until she brought forth her firstborn son" is "up to the time that," because it only informs us what Joseph didn't do up until a certain point, not what occurred after that point. For reasons explained, the word "until" in Matt. 1:25 isn't evidence that Joseph and Mary had or didn't have intercourse or that they had or didn't have children after Jesus's birth. The importance of Matt. 1:20-25 is that it primarily pertains to the messianic prophecy, not the sexual relationship, or lack thereof, between Joseph and Mary.
How's Jesus being called "firstborn Son" evidence that shows He had siblings?