Currently, the only official UI customization available is or White modes:
If you are a graphic designer or just want a "Switch-looking" interface for a video or stream overlay, you do not need the actual OS. nintendo switch ui download link
Never download "Official Switch OS" files from third-party websites. These are often malware or corrupted files that can brick your console. 🎨 Custom UI and Themes (Atmosphere & NXThemes) Currently, the only official UI customization available is