Sub Collection Array Query Conundrum

I'm experiencing a little dilemma when querying lists within multiple documents of a sub collection.

Here's a sample of the current DB setup:

Parent Collection (Reports)
———Document XYZ
——————Sub Collection (Photos)
—————————Document A
————————————Photo URL (list)
————————————Created By (string)
————————————Post Reference (reference to Document XYZ)
—————————Document B
————————————Photo URL (list)
————————————Created By (string)
————————————Post Reference (reference to Document XYZ)

Here's the widget tree:

Container (Query Collection of Photos)—there's a parameter referencing Document XYZ
——— Column (Generating Children form Variable)
—————— Image

The issue I'm experiencing is as following, based on different settings:

Setup 1: Getting a list of only Document A

Setup 2: Getting first image of each Document

Expected result:

I need to get a list of all images (Photo URLs) within all documents in the Sub Collection (Photos) found in Document XYZ.

Guidance is appreciated.