Apple does keep older iPhones on sale — at present it sells the iPhone 14 and iPhone 15 alongside the iPhone 16 range.
In early January 2025, a seemingly unlikely leak claimed that the iPhone SE 4 would be renamed the iPhone 16E.
If all of this is correct, then the iPhone SE 4 is looking to be significantly closer to the current iPhone range than before.
Overall, it's expected that the iPhone SE 4 will physically resemble the iPhone 14 from 2022.
iPhone SE 4 is rumored to resemble iPhone 14.