For what it's worth, I did meet one of the UA ops managers and a GS agent during a DEN cancellation issue on a connecting flight. Prior to COVID I was told that DEN-AMS was going to be launched with the 788. These plans were scrapped of course. My contact in AMS (I live in AMS) before they closed the international UA office at Schiphol confirmed this and also stated that UA would open a Denver Polaris lounge when they had 7 UA international Polaris destinations. The latest rumour, although not confirmed was that Denver would get AMS after all, as well as CDG. This would push the UA total flights to 7 and then would have the LH flights as well bringing it up to 9.