I'm sure early humans were at least as capable at making beds, and could make something that functioned as a pillow, or at least gave some neck support, if that was comfortable.
(To be clear, I know absolutely nothing about how early humans slept. I just suspect that you don't either.)
What makes you think early humans slept on flat surfaces with no neck support? Is this something you've studied, or are you making things up?
Here's what gorilla nests look like:
https://www.berggorilla.org/en/gorillas/general/everyday-lif...
I'm sure early humans were at least as capable at making beds, and could make something that functioned as a pillow, or at least gave some neck support, if that was comfortable.
(To be clear, I know absolutely nothing about how early humans slept. I just suspect that you don't either.)