We can put it in a simpler way that the OnePlus 13 and 13R have the same kind of phone-family dynamics, as it gets when two siblings are in the same family. The 13 is the older one, which is entitled to new and better stuff first. By this, we mean faster speeds, higher resolutions on the images, and seamless display transitions.
Meanwhile, the 13R is the younger and cooler little sister who is innovative and experimental but cannot give it her all owing to the constraints of cost. You can send messages, watch movies, and even capture photos with each one of them equally. But even with all that, it is interesting that put into scrutiny the 13 is much better at handling powerful video games or editing heavy and giant applications because of its more powerful processor.
The 13R is also not slow; it will also run those same applications but not as quickly. You will. Cameras are taking a hit in the performance gap as well, as the 13 captures more detail in low light, and the 13R provides decent performance but only in the daylight. The batteries both last roughly the same amount of time, but the 13 charges in three less minutes than the 13R. If you spend long hours in front of the phone, then 13 will surely not disappoint.
For someone who loves aimlessly browsing the internet, then also that person is the right market for the 13R. The 13R might see a lot of students buying it for taking notes and using various messenger apps, while the 13 will see more patrons among shooters and fishers whom to expect.