Selecting from nearly identical background color


I have an image with a background that is less than a tolerance of 1 different (in places) from the things I am selecting. I have viewed many, many videos about selection and none help me.
I can see the distinctions with the naked eye (e.g. in the first image, there are places where the edges between a cream colored mannequin neck is against a cream colored background, but the distinction, however tiny, enables me to see the margin. Photoshop does not seem to like as subtle a distinction?
I have tried:
Both quick selection and magic wand tool
Refine selection (this is tricky because the selections are filled with black at about layer 15 and the Background Eraser Tool does not seem to pull from the Background image (I assume it is supposed to come from the first layer Background image since it's called Background Eraser Tool??)
magnet tool (for more specific areas.)
Grow and contract selections
Erasers, background eraser, layer masks, to restore parts of the image that have been selected that in fact should remain (e.g. a selection includes one side of a leg when that side must remain in the original.
Selection with a tolerance as low as 1.
I am using Photoshop CC 2019 on a powerful PC with excellent graphics card (if that matters).
I am attaching both the original and a masked copy with my many hours of selection efforts, isolated. As you will see, sections of the selection are missing.
As many have noted on this forum, there are numerous videos about selection which seem to focus on hair, and things on contrasting color backgrounds (e.g. blonde hair on dark solid background)
