Isn't every game from now on required to have some kind of Pro improvements? Or did that turn out to be false? Not sure if Sony ever confirmed that or if it was just a part of the leak from a while ago.
You're misremembering the leak. As described, every game would be required to submit for certification with the new SDK and be certified in the console's Pro mode. That doesn't mean the game needs 4K support, it just means the hardware runs with the full GPU resources and higher clock speeds enabled. I see no reason why Sony would relax this, so every new game should be different on Pro they're just not guaranteed to have amazing, smooth IQ from supersampling.
How a developer uses the more capable hardware is up to them, except for the leaked requirement that 1080p be used as the minimum resolution.