I have field of Umbraco.MediaPicker3, this has been upgraded from Media Picker (legacy) and from Umbraco 8 to 16. Problem is that it returns null for files ( .pdf, .docx ) works as expected for images.
I have the following code to return the media for files:
var attachment = Model.Value<IEnumerable<IPublishedContent>>(“fileAttachemnt“)
Just checking - you have a typo in the property alias (fileAttachemnt => fileAttachment ?) – would be sad to find out after years of debugging that the culprit was that!
Otherwise I’d suspect that you could try using IEnumerable<MediaWithCrops> as the type (as per the documentation here: Media Picker | Umbraco CMS) to see if that gets you closer?