Does anyone here run any of these OSes on any of the offered screen densities and resolutions? I have questions. - Surely not every old program available from the repositories will work with display scaling, will they? I've never had to use it, maybe Xorg has some hack to scale certain windows at 2x so you don't need support from individual packages. I'm also thinking of things like Burp Suite, which have window-like…
- I don't have a 4k display on a laptop so can't comment on battery life. But for "desktop use" (read: non gaming) GPU performance has been fine for a long time. I have an old desktop at work with a 4th gen i5 and whatever the integrated GPU was at the time. It can drive a 4k panel at 60 Hz just fine. A somewhat newer laptop, 8th gen i5 with a uhd620 integrated GPU could drive its internal FHD panel and an external UHD display without any issue.
- For your eyes comment: the small fonts may be illegible because they're blurry. On FHD screens, I've found that bitmap fonts are much more legible at small sizes. I've seen some Dell with a 4k display at work, probably 15", and the small text was much more legible than on my 14" FHD laptop (compared using Windows 11 - the guy was a Windows dev).
- TV has a blurriness to its movement, so it looks smooth enough because it's never actually sharp. The point of higher refresh rates is not "flickering", but a smooth movement. Try reading a scrolling page on a 30 Hz, 60 Hz, 120 Hz screen. I mostly look at static text on my screens, so 60 Hz works well enough for me, and I prefer higher resolution / better colors to higher refresh rates. Don't know how this affects GPU usage, though I don't expect it to be "free".