Yes they should put HUGE batteries into small phones!!!
/s

Seems like a straw man, because I can’t see a single comment claiming that.

I’m guessing it’s because most women carry their phone in a bag, so the bigger phone isn’t inconvenient and has the advantage of the bigger screen.
And I suppose most men prefer the bigger screen size, and they are convenient enough in the available sizes. I use a 6.7 inch, and it fits fine in a pocket for me.
Also note that although we have way bigger screens on modern phones, the bezels are way smaller, on the first smartphones the screen was only about 50% of the front face. So a 10 year old 4 inch phone can be about as big as a new 6 inch.

this one looks much too “tidy” to be true: no tubes, cables etc.

You mean like this?
https://www.youtube.com/watch?v=YD9EaS3VRbc

Boston Dynamics used hydraulics, for their older generation bots, but AFAIK the new ones don’t, so there is no tubing or wiring visible on new models.

If free will is an illusion, then what is the function of this illusion?
Alternatively, how did it evolve and remain for billions of years without a function?