Dell S2719DGF - bad picture on the PS4?

A Dell S2719DGF purchased very fresh on Black Friday, arrived today and just connected. Problem? On the PS4, the picture is blurry. I had a BenQ RL2455HM before and since the quality of the picture was much better than here with the Dell S2719DGF. Can someone please help me by chance? On the Ps4 and on the monitor, I already rumgefummelt here respect, without success. It can't be that a 60 HZ Full HD monitor (my previous monitor, the BenQ RL2455HM) dissolves better than my new monitor (155 HZ WQHD Dell S2719DGF). Even if the WQHD and 155 HZ bring nothing to the PS4, the Dell is 3x as expensive as the BenQ, since you could at least expect at least the same quality right? I can't shake the feeling that it is a matter of attitude, which can't seriously have such a dirt resolution in the PS4? The monitor was so highly praised as if it were so kagge.

I'm not sure, but I think that it is because the monitor is not running with its native resolution, but only with 1080p