Desktops naturally seem to get the
The higher resolution display cannot add detail to any raster content—things like videos, images, they are the resolution that they are, and the display simply presents the content. If you playback a 1920 x 1080 video fullscreen on a 5120 x 2880 display it will simply be upscaled to fit the canvas, and this is usually done pretty well, given that scaling from 1080p to 1440p is not a simple nearest neighbor upscale—the canvas is 1.33 times as large in each direction. When i play back a 1080p video i usually do it on my secondary 3840 x 2160 display because that is an even 2x integer multiple of 1080p in each dimension. But that is some nervosa stuff—the reality is that an iMac 5k display will playback lower res content at fullscreen in a way that’s indistinguishable from the original—display upscale tech is good enough. One thing is that when you watch 1080p content on that large of a screen from that close up it looks bad because the pixel density is low. But that’s to be expected. Don’t expect any extra detail in existing content, but not expect any less either.
What about the videos on iTunes that Apple has had like HDR, 4K? I do edit photos as well for a hobby, I love the big 27” screen on my current iMac (2012) so I don’t want to downgrade to the 21” version.