Should I use a TV as a computer monitor?
You can, and for some uses it works well — but several differences make a TV a poor desk monitor and a good living-room display, and they are not obvious from the specifications.
Where TVs fall short:
Pixel density. This is the biggest issue. A 27-inch 4K monitor has roughly 163 pixels per inch; a 43-inch 4K TV has about 102. At normal desk distance, text on the TV looks noticeably coarser. Larger TVs at 4K are worse still.
Subpixel layout. Many TVs, particularly some LCD and WOLED panels, use subpixel arrangements designed for video rather than the RGB stripe that desktop font rendering assumes. The result is coloured fringing on text — a real and frequently reported problem that no setting fully fixes.
Input lag. TVs apply image processing that adds latency. Game mode bypasses most of it and is essential; without it, even mouse movement feels detached.
Chroma subsampling. Many TVs handle full 4:4:4 colour only on specific inputs or in specific modes. Without it, coloured text becomes blurry. Check the manual for which HDMI port supports it.
Ergonomics. TVs lack height adjustment, tilt and VESA positioning suited to a desk, and a 43-inch panel at arm's length requires head movement rather than eye movement.
Overscan and sharpening are often on by default and must be disabled.
Where a TV works well: as a secondary or occasional display, for console gaming, for media, for presentations, and for anyone who sits further back. A 42-48 inch OLED at a longer viewing distance is a legitimate choice, and some are marketed for it.
Burn-in is worth considering for OLED with static taskbars and windows, though modern mitigation has reduced the risk considerably.
Check refresh rate support at the resolution you want — many TVs do 120Hz only at reduced settings.