By 4K (1080) I meant that a 4K screen has a typical resolution of 3840x2160, which gives you at 2x scale factor an equivalent screen estate as a 1920x1080. That's too little screen estate for me.

The screen you referenced would be even less than that at 2x scaling factor: 1920x900, which is even fewer screen estate. A 4k ultrawide is not retina, so doesn’t cut it.