The linked to HDMI to DP adapter is insufficient to solve the connection problem between the PS4 Pro and OP's screen. He's already got an HDMI 1.4 input, he doesn't need another one. The adapter also specifically states a lack of support for HDCP 2.2.
As mentioned by a manufacturer of such adapters, the problem is not their willingness to make such a thing, it's the lack of a chipset that can convert HDMI 2.0a to DP 1.2 being available at this time.
So, basically, they don't exist because right now it's not possible. It's not a technical impossibility, just hasn't been done yet. It should happen in time.
The solution then is to get a different screen or run the PS4 Pro through something like the PSVR, which does appear to be working...