Don Pacifico I don't think it's clear at all. Havertz had the nod in the Champions League final and perhaps one or two other games, but there's not a strong weight of evidence either way around it. The numbers in terms of minutes/appearances would suggest it's Gyokeres, but that doesn't necessarily recognise the fact Havertz was still coming off a long lay-off.
Which brings me to the point, he can only be number one if he's fit. At the moment we can't rely on him any more than Timber, White or Calafiori.