Bug: Resolution 5120x1440 not working

According to apple support, the super ultrawide resolution is currently not working because of some operating system issue. While the "more sqare" resolution of 5120x2880px is supported by the newer Mac Air, Mac Pro etc., a subset of that cannot be chosen.

This is contrary to what is proclaimed by apple in the tech specifications!!!

The option to use SwitchResX does not lead to true 5120x1440: It just scales the next smaller resolution (3840x1080), resulting in a pixelated picture.

This holds true for all super ultrawide monitors such as Phillips 499P9H, Samsung C49RG94SSU, DELL UltraSharp U4919DW, LG 49WL95C-W, and similar.