Going off my post here since it probably better fits as a suggestion.
Using a 4k compatible setup, the only quality options to change to are transcode options. Even when a manually added 1080p version is readily available for non-compatible setups.
Both viewing the same content, yet the 4k compatible setup is unable to select the 1080p version the incompatible setup is using.
Adding pre-processed (other than Plex’s optimized versions) qualities to the options would reduce transcode load, which is extremely limited in the context of 4k content.
I want to be clear I that I personally think it is a worth while idea to include them in the list. Please don’t take me describing how it currently works as thinking this a bad idea.