The name of this new SE phone, 16E, fits with the currently available lineup of iPhones, which all have 16 in their names. But that'll change in September, and again in September 2026.
If Apple continues updating the SE model every 3 years as they have for the previous SE models, then in September 2026 the lineup will include 4 or 5 phones with "18" in the name, plus the iPhone 16E.
But maybe Apple now plans to do annual updates to the SE, even just a chip update. Then the it's naming can be in sync with that of the other iphones.