I use a 1080p monitor and what I’ve noticed is that once creators start uploading 4k content the 1080p version that I watch on fullscreen has more artifacting than when they only uploaded in 1080p.
Did you notice that as well?
Watching in 1440p on a 1080p monitor results in a much better image, to the detriment of theoretically less sharper image and a lot higher CPU usage.
The one I’ve noticed is that for videos with the 1080p “Enhanced Bitrate” option, the free 1080p video looks like a blurry mess compared to normal 1080p content.
From my experience it doesn’t matter if there is an “Enhanced Bitrate” option or not. My assumption is that around the time that they added this option they dropped the regular 1080p bitrate for all videos. However they likely didn’t eagerly re-encode old videos. So old videos still look OK for “1080p” but newer videos look trash whether or not the “1080p Enhanced Bitrate” option is available.