Why do documents go gray or become unavailable to open? Also, why is it so hard to find a document to upload right after creation of it?

When Pages opens its Open File Chooser, it will gray those files that it is not designed to open such as PDFs, images, or other incompatible document types. The Pages Save panel will have all files (but not folders) grayed out as the goal is to not risk overwriting any previous documents.

When you save a Pages document, it will remember that save location for subsequent documents until you change the location again. Sometimes, just knowing that information will help locate the previous Pages document.

If you have the Spotlight Documents search result category selected and Spotlight is indexing your local drive, then you can find Pages documents with Spotlight reserved words from the menu 🔍 Spotlight tool, or a Finder Window search field:

Find any Pages document created before Jan 1, 2023:

kind:pages created:<01/01/2023

Find any Pages document created after Jan 1, 2023:

kind:pages created:>01/01/2023

Find any Pages document created in a date range:

kind:pages created:06/01/2022-03/04/2023