If it was in Tray you would have it in your library. So if you do not have it in your library then the Tray files can not help you. Try to see if you can restore an older save.
My tray is full with files from 2018 to 2023 and I do not have that many in my gallery, so I think I might have it there. However I have no idea how to find it.
In the Gallery mode, click to your Library. That's the items you saved to your Library while you were in Build mode. You can use the search or just scroll through items. If you didn't save the build to your Library or upload to the Gallery, though, there's nothing there to recover.
