Shredded latex is the answer, 100%. But only if you are able to remove (or add) the latex as needed. I found I needed about half of what the pillow came with. Maybe a third?
The result is a pillow that can do it all: prop up your head for reading in bed, become mostly neck support for back sleeping (with a bit of shaping; takes seconds but isn’t automatic,) and ditto for side sleeping but at a slightly higher height.
Once you get used to a pillow that holds its shape and provides excellent support, all other pillows feel archaic.
Last one doesn’t make sense any more, iPhones have been usb-c for a couple years now.