Star Wars: Rise of Skywalker Featurete
That beginning blooper, has that ever been shown to the public?
This featurette was first shown at the Star Wars Celebration in Chicago, IL on April 2019 just before a panel discussion. A cell-phone recording of this blooper reel with audience-reaction sounds was upload on the 'spleen shortly after.
Thanks, @TavorX, for finding a better quality video.