Sony, with the 5 V, will probably target the iPhone 14, which is more popular than the 14 Pro, and compete with the Pixel 8 and the Zenfone 10, and leave the 1V as the full featured flagship like the 14 Pro Max, Pixel 8 Pro, S23 Ultra...

Small consolation price : 5 V may be cheaper than 5 IV

Not sure, Apple with the iPhone 15 increase their battery capacities while having an efficient CPU, so maybe Google doesn't want to be relegated. It's difficult to offer a 1-day battery life when your main opponent is leaning towards 2 days.