Catch the spin from Ed on iNames:
Names are about branding, and branding is about differentiation. Even Apple’s older iPhone names– 5 and 5s, 6 and 6s, et al– were obvious and identifiable among competitors. Even that died with iPhone 7. That left Apple with the alphanumeric craze of iPhone XR, XS, and XS Max. Those, too, have died.
What’s left? Pro.