Samsung
Change Theme (Display & Home Screen) auf Samsung
Samsung phones running One UI store personalization options separately from the wallpaper settings you might already know. A theme bundles icons, background, and in some cases the visual style of built-in apps into one package. Downloading a theme from the Galaxy Store only saves it to your device. It does not automatically replace your current look.
To apply a downloaded theme, open Settings ➔ Themes. Inside the Themes app, open the menu and tap My stuff. This section lists every theme you have downloaded or purchased. Choose the theme you want, then confirm with Apply.
If the theme you expected is missing from My stuff, it likely was not downloaded correctly or was removed in a previous cleanup. Re-downloading it from the Galaxy Store usually fixes this.
Applying a theme changes icons and background together. If you only want a new wallpaper without touching icon style, use the separate wallpaper settings instead of the Themes app.

