Well, there are scientists who know an awful lot about the chemistry of wine; certainly much more so than people did 2000 years ago. If it were possible to instantly convert water into wine, we'd know about it, or at least have some idea about how it was conceivably performed.

For the fantastical accomplishments of people of thousands of years ago to be believed, there needs to be more concrete evidence than stories passed down for generations. In this situation, it's unlikely that such evidence survived, so the best we could do is replicate what happened in the past and determine whether or not such an accomplishment could have happened given the technology of the past.

I believe that people 5000 years ago could build awe-inspiring structures from stone because there's plenty of evidence of such capabilities (i.e., the great pyramids). I don't believe that someone turned water into wine instantly, because, afaik that is not possible, thus, at best, the event in question was some sleight-of-hand magic trick.

Christianity teaches that Jesus was God, so in that story, the same person who created all the atoms in the universe turned water into wine, presumably with the same power.

That’s only to say you have a more fundamental disagreement than the truth about this one incident.

Jesus created all the atoms in the universe?

Christianity teaches that a Jesus is God and God created the entire universe.

Several religions beg to differ. What do you think about that?

I agree that’s the case. I only pulled that information about Christianity for the OP because they weren’t sure what Christianity taught about the water-wine parable.

to me, it was Jesus being a nice bro, and bringing lots of wine to the party, coz he was cool.