Also 3), bringing your couch and TV closer to each other will probably result in some wasted space around them that you can't use in any way (like 0.5m behind t

Also 3), bringing your couch and TV closer to each other will probably result in some wasted space around them that you can't use in any way (like 0.5m behind the couch and the TV stand). Not quite a worthwhile compromise. Not everything is about optimizing for the numbers. You don't have to plan your TV watching experience to the mm in order to enjoy it. You can have the TV at a slightly non-optimal distance, use the integrated speakers, or view content that's not high bitrate 4K or FHD.