The naming scheme is both a mess, and has huge brand recognition all at the same time.
Two iPhone related naming schemes have been like clock work for years; iOS and the A chip. Sync the iPhone model name with those 3 facets of the device; design, operating system and chip, all one. It’s the best thing about iPhone, that they’re all made for each other anyways.
This years 3 models will be called iPhone 12. Choose your size at purchase.
Or if they have to differentiate;
iPhone 12(6.1)
iPhone 12X(5.8)
iPhone 12XL(6.5)
12 also keeps the appropriate distance from Samsung galaxy phones, numerically.