The official iOS Reddit app was already from a purchased third party client that people used to like (AlienBlue).

The issue is the popular apps will inherently be at odds with Reddit's goals, because popular apps are popular due to their user-friendly experiences, and Reddit doesn't want a nice app where users can get in and out without interference. They want dark patterns that get you mindlessly scrolling forever, showing you ads, and tracking every tap and fling you do.