Display Resolution
At a certain point, display resolution doesn’t really matter since the naked eye can’t really differentiate individual pixels. But, on paper, some displays will still be better than others. In this case, the Samsung Galaxy S10e has a better display.
For one, it’s an AMOLED and Full HD+ display instead of an LCD. It also packs in more pixels and comes with support for HDR10+. That should result in a better picture. But, of course, it may come with a downside. The iPhone XR’s lower-resolution display is a serious battery saver.
Winner: Samsung Galaxy 10e.