FWIW, the Travel Ready center on the UA (desktop) website DOES let you upload an image of the passport. I have what I think is a pretty good scan of my passport, but I cannot get it to register either via the desktop upload (where it does pull in the data) or by taking a picture of the image file on a monitor (laptop and desktop). Unfortunately I'm traveling so don't have my actual passport, but was hoping a good scan would work. Hopefully I'll be able to get a picture of the actual passport to work, although I believe it's one of the shiny ones people have had trouble with (2021 issue).