Do you prefer the headphone jack to be at the top or at the bottom on a phone, and why?

I need a port on each side.

USB-C on the bottom.
3.5mm audio on top.
RJ45 on the left.
SCART on the right.

This is the right answer, in my opinion.

If you are of the pants with pockets wearing disposition, then whichever side of the phone faces down will inevitably end up filled with dust and lint. Having both ports on the same side makes this a trivial problem.