That looks like a screenshot from the Plex Web app. If it is, I don’t believe many web browsers support the HEVC codec used in the 4K version (from the XML)
So, Plex is choosing the correct version for the player to avoid transcoding. Manually selecting the 4K version will likely force the server to transcode to the x264/h264 format anyway.
If that is a screenshot from a device/app capable of playing HEVC 4K videos, than it is a different problem, and my comment is probably irrelevant.
I see similar if I have an HEVC video and H.264. The web app always selects the H.264 version, but apps (like my Roku, Android TV, etc) auto-magically select the HEVC version