If this device is that far along, then if Apple was smart, they would use the next 7 months to ramp up production. Maybe have it come out the same way the iPhone X did.
Back in 2017, the primary iPhone for that year was iPhone 8 series, but Tim Cook being the carnival barker that he is told they had one more thing to show us.
They could repeat that pattern again this year. Show off the iPhone 17 series and then tell us they have one more thing to show us. While the 17's could come out in September, they could have a delayed launch for the iPhone Fold. Just like the X, have it pre-order in October and launch in November.