To troubleshoot the blur on the Smart TV, there are several steps you should take to try and fix the issue:

1. Check all the connections between the cables and ports
2. Check the cables, display ports, and adapters for signs of damage
3. Ensure you have the correct settings and resolutions for your desired display choice
4. Adjust the picture-in-picture settings
5. Restart the Smart TV
6. Check the display settings for any picture or image settings that may be causing the blur
7. Ensure that the picture on the Smart TV is synced to your external devices
8. Update the display driver and video card