The following menu action was removed by Google in 4Q2024. There is no longer a method for adding shared albums to your album data.
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By default, Google does not include albums shared with you in the list of albums given to apps.
Visit the shared album on https://photos.google.com and select “Show In Albums” from the vertical … menu inside the album. That will allow the album to appear in your list of albums and in pixFolio. You should then be able to refresh the albums in the app and see the album.