At this point, until more factual evidence is found and presented, the saga reminds me of “The Wizard of OZ”.
So true but I was presenting possible failure modes that might help during discussions with the dealer. I too am baffled why/how the middle cylinder failure occurred so rapidly. And is the immediately previous oil change a coincidence or a cause?

Unfortunately the oil has already been changed since purchase which is why I recommended an oil pressure check rather than an oil sample analysis.

At this point this is probably the best course of action
This weekend, I'm going to put it back together enough to get it inspected and registered, change the oil, and do some longer rides to verify it is using oil like he says it is.