Other than that native resolution do the rest become a little blurry
Let me elaborate on this a bit. The built-in Display Settings list the resolutions I have pictured above. They are Apple's "recommended" available resolutions and they all appear clear and sharp. But I also use
RDM to quickly switch between ANY resolutions available, including the ability to indicate which ones are HiDPI. There are other apps out there that offer this capability and much more, but RDM is free and I don't want or need the other features.
The ones in the (rather long graphic) list below are what is available for the
LG 34WK95U using RDM and the ones with the little lighting bolt are HiDPI resolutions. Those resolutions will appear crisp and clear. The other resolutions are perfectly useable, but not nearly as sharp. Oddly, the native resolution of this Display doesn't show as HiDPI, but it's perfectly clear and sharp.
One caveat is that not all the HiDPI resolutions work on all external displays. On a built in Retina screen this doesn't seem to be an issue, but for external displays it is. For instance, the 3840x2160 resolution doesn't work on the LG34WK95U - which makes sense, because how would you get the native height, but not the full native width without distorting the picture. When I click that resolution, absolutely nothing happens.