There hasn't been any significant upgrade for iPhone and smartphone in general in years.
I'd say anyone with a iPhone 12/13 or older and wants to upgrade now don't need to hesitate. There are plenty of discount opportunities on Shopee/Lazada. Even if you wait another 5 months for iPhone 17, it's not going to be a much better phone. It's also more cost friendly to get an older phone.
If you don't fancy the camera control button, try exploring the 15 series instead. You will have less headache with cases as well.