I had an Oppo F1S for a few weeks, it had a gesture whereby you could swipe and reduce the screen size to something like 60%[1] (guessing) thereby enabling one thumb reach.
My daily driver is an iPhone SE, I have average / medium sized hands and can reach the whole screen well enough.
1. http://androidaustralia-zippykid.netdna-ssl.com/wp-content/u...