I use a 4K 43" Samsung TV as a monitor. I can just get the whole width in my lateral field of vision, but I really need to move my head slightly to gain sharp

I use a 4K 43" Samsung TV as a monitor. I can just get the whole width in my lateral field of vision, but I really need to move my head slightly to gain sharp visual focus all over the screen. Wit a vertical 'resolution' of 2160, it gives me lots of lines of text.