The scholarly consensus is that when Matthew quoted Isaiah’s prophecy - which he quoted almost exactly - he used a mistranslation. We know this because the same mistranslation was common in the time period. However, we have OLDER manuscripts which do not have this error. So we know he made this mistake. Also, we have critics of Matthew in the second and third century calling this out. They knew almost at the time Matthew wrote the Gospel he was wrong. No one argues this. We have the evidence. The conclusion - which you CAN argue - is that he made up the virgin story because he thought that’s what the prophecy said. The letters of St Paul don’t mention a virgin birth. The gospel of Mark doesn’t. John doesn’t. No historian does. Matthew barely mentions it, and Luke pretty much copied and extended/changed Matthew. Many of the earliest Christian sects didn’t believe Mary was a virgin. Heck, Matthew was written almost a century after Christ was born. How did Matthew know about this and no one else before him mention it???
Well, you are now changing your position. I won’t argue the above. That’s theology. In fact, I agree with it.
But the FACT remains that the Bible REPEATEDLY refers to Jesus as having brothers and sisters. Josephus says the same. You made the argument that certain Middle east translations of the Bible use words that can also mean ‘cousin’. This is a stretch, but you can interpret it that way. But, the original Greek clearly states that Jesus had biological brothers. Not spiritual brothers. Not cousins. Real biological siblings. The Bible also clearly states Joseph is the biological father of Jesus - it even lists the genealogy multiple times.
People get upset when they learn this. It’s like their faith is shaken. But that shouldn’t be - you should question the institutional leaders of the Church that try to subvert facts and true history, but not the fundamental message of Christianity. So Mary wasn’t a virgin? It really doesn’t bother me. I’m still going to live my life as a good person.