I'm just gonna say it but DLDSR, whilst excellent, native 4K is the crisper picture, although that verdict is a bit unfair as we're going from a 110ppi OLED to a 140ppi (I think?) - So the native 4K was always going to look better in games. On the desktop because Windows is doing scaling, things look no real different other than some stuff being bigger now because of the default Windows scaling.
But in games, in games the native 4K is the real deal, it's just cleaner and sharper than DLDSR 5160x2160 on the 34", and performance is better too because of no driver overhead having to do the DLDSR part to get that res on top.