It's important to note that the resolution at which streaming apps like YouTube run on your TV can be influenced by various factors, including the TV model, the app itself, and your internet connection. Here's some information to help address your concern: The LG UHD 43UP76 is indeed advertised as a 4K UHD TV, capable of displaying content in 4K resolution. However, the YouTube app's resolution may not always match the TV's native resolution. WebOS, LG's smart TV operating system, typically supports various resolutions, including 4K. However, the resolution of the user interface (UI) and apps like YouTube can vary. The UI may run at a lower resolution like 1080p while content playback should ideally be in 4K if available. YouTube's resolution can depend on several factors, such as the source of the video, the content creator's settings, and your internet speed. YouTube is known for adaptive streaming, where it adjusts the resolution based on your internet connection to ensure smooth playback. To maximize YouTube's resolution on your LG TV, ensure you have a stable and fast internet connection. Additionally, check the settings within the YouTube app on your TV to see if there's an option to manually set the playback resolution. If you are playing 4K content on YouTube, it should be displayed in its native resolution. If it appears downscaled, it might be due to a setting or issue specific to your TV or the YouTube app version. You can check the LG webOS community forums for discussions on similar issues and potential solutions. In summary, while WebOS may have a UI that runs at 1080p, it should still be possible to stream and view 4K content on your LG UHD 43UP76 TV through apps like YouTube. However, if you are experiencing issues with resolution, it's worth checking settings, your internet connection, and seeking assistance from the LG community for specific troubleshooting steps.