The claim in John is that the author got his information from an eyewitness. The alleged eyewitness is not identified, and no eyewitness account of any historical event is attributable to that person from the text. John is written about 100 CE, seventy years after the customary date for the crucifixion, and it seems highly unlikely that any part of John is based on eyewitness accounts; but whether any part is or not, that doesn't make the author of John an eyewitness, and it leaves us where we came in, with precisely zero eyewitness accounts, actual or claimed. (There are claims here and there to have had visions of Jesus, or to have seen Jesus' 'glory', and so on, but they're not eyewitness accounts of anything historical.)