They can easily implement AMD FSR. It's open source and imo better than dynamic scaling.I don't think I've seen it mentioned here yet, but it's possible we could see PD's first (?) implementation of dynamic resolution scaling to particularly help the base PS4 version. This is how PCARS 2 achieved what it did. That game didn't always run well on consoles, but PD's go of it would of course be better/more efficient at least thanks to their intimacy with PlayStation hardware.
This is speculation of course, but I think the PS4 Pro could do well at 1440p with little/no DRS. It's a small step down from GT Sport's 1800p, but perhaps necessary to make room for the added system load that dynamic weather/lighting introduces. I see a 900p future for base PS4.