https://www.cnet.com/news/new-1440p-support-helps-xbox-one-play-nice-with-qhd-monitors/

The Xbox One X is adding support for QHD resolution output. 

The Xbox One X and Xbox One S already both support 1,920x1,080 (called FHD) and 3,840x2,160 (4K) resolutions. But many PC monitors use an in-between resolution of 2,560x1,440, also called QHD. The new Spring Update adds native QHD support, so those displays can now get pixel-for-pixel output, which could result in sharper images.