Finally saw the video during the YouTube release and here's my interpretation.
Carrie and John are both angels who descended from heaven and they visited an abandoned church to do some sort of a rendezvous. They then join each other in singing a hymn, prayer detailing their hopes and wishes for the world. The images of people are flashbacks to when people are free to visit churches and celebrate. Not many countries allow open worships today because of corona.
At the end, you can see John and then Carrie vanish, signaling the end of the prayer.