I don't know if it carried over into 4K TVs, but I'm surprised that the dreaded HDMI overscan isn't mentioned anywhere. I'll never understand WHY and HOW someone thought that implementing this at all, let alone making it the default, is a good idea. You had one job, accept a 1080p signal and output it pixel-perfectly to the 1080p display panel. Yet somehow, someone thought that it would be a great idea to cut off the edges of the image and interpolate it so everything looks atrocious. And then every single TV manufacturer agreed and implemented it. Whenever I see this kind of cropped image on a TV, I grab the remote and set it to the only mode that should exist on digital displays, direct pixel-to-pixel mapping. Just blows my mind I have to do that.
I have an Aorus 4K Display [Gigabyte], which is technically "not just a TV screen," and in order to defeat the overscan mismatch [having found no method functional either in OS or on TV settings] I plug the HDMI cable into a DVI->HDMI adapter [instead of HDMI direct from TV to HDMI output].
For some reason, this dongle hack, de-necessitates the overscan settings [which never seem to work/hold]. But of course then there is no 4K output [which is fine].
From my previous reading on the subject, HDMI comes from the TV world, and DVI comes from the computer monitor world.
On a computer display, you want each pixel to be square and to be visible on the screen, a border around all the pixles doesn't matter.
On a TV, historically, pixels didn't exist, and the nearest concept to a pixel (I forget the term) wasn't square, it was rectangular. Showing a border around the content is not acceptable, and it should go right up to the very edge. Also in the TV world, the most important thing in the image, not the pixels.
So it's this philosophical difference, and separate histories, which means you should never try to get a TV to be a monitor, or a monitor to be a TV. Of course I only learnt this after buying a device which said it could be both.
It's rare but some source material is created with the assumption of overscan, whether that affects on-screen graphics or even some cases just total garbage is produced into the overscan areas... it all varies, but from the TV maker's perspective, doing what you're describing means this garbage never appears and they never get calls from confused angry customers who think their TV is broken because some broadcaster has some garbage at the edge of the feed.
