One should be at the bottom one at the top. I understand space on the phone is a premium but a second port would make the phone so much more usable. Wired headphones, flash drives, camera modules, speaker modules, keyboards, even connection to a TV, all could be used while charging. It’s a shame it’s not a thing, USB is extremely versatile port, but you only get one and it’s used for charging half of the time. (I am aware dongles exist)
I agree. If we’re going to lose the headphone port in favour of connecting to a universal connection (either directly or via an adaptor) then it’s time we have two of them. As for positioning I gather that there are lots of handheld PC’s with the one on top and one on bottom configuration and that it’s generally accepted to be the best way (and my on top 3.5mm and on bottom USB-c seems to work pretty well) so I think you’re right but it would be nice to see manufacturers try out a few different configurations to see in practise what people prefer.