Earlier quoted context omitted.
My previous phone - Asus Zenfone - featured the one-hand mode, where you scale whole viewport down and move it on the screen as you see fit. See this image: https://www.technokick.com/wp-content/uploads/2015/05/DSCN79... Maybe not beautiful but it was practical in some cases. More vendors should ship things like this. But the companies value fake visual niceness over usability so I'm not holding my breath.
iOS has Reachability[1] which is a similar solution the same problems. The problem with solutions like this is that they are often hard to discover. 1: https://support.apple.com/en-gb/guide/iphone/iph77bcdd132/13...
I assume it is because the screen is the ‘correct’ size on the SE.