- Motion Blur
- Resolution scale
- Temporal Anti Aliasing
Those are the three causes for Unreal Games to look blurry. You already disabled motion blur. The next one would be to ensure that the resolution scale isn’t below 100% (the big “Settings” button → “Engine Scalability Settings”).
Disabling TAA is generally not a good idea, because it’ll introduce aliasing. UE4 has four AA algorithms by: TAA, FXAA, MSAA and SSAA.
TAA has the downside of introducing ghosting (the afterimage you can see on your first screenshot) and reduces texture detail (which creates the overall blurriness).
FXAA is a worse (but faster) TAA, if you wish. Since it’s not a temporal algorithm, it doesn’t introduce ghosting, however, it still screws with your texture detail and makes everything less sharp.
MSAA is the slowest of the three “normal” algorithms and does not reduce texture detail. However, it only works with the forward renderer and is broken for foilage (no ATOC).
SSAA is a special one. In terms of effectiveness it’s the best, because it not only doesn’t reduce texture quality, it even improves the it due to how they are filtered. The downside of SSAA is that it’s just not viable to use for the most part, because it comes with an enormous performance penalty. Generally speaking, the use cases of SSAA are making pretty screenshots and the playing the games of yesteryear on the powerful hardware of today. You can enable it via console, by setting r.ScreenPercentage to values above 100 (doesn’t show in the editor preview, you need to play).