Samsung
Set Default Home Screen Launcher auf Samsung
On Samsung phones, One UI acts as the default launcher and controls the Home screen, app drawer, and gestures. Installing another launcher from the Play Store adds it as an option, but Android does not switch automatically. The system keeps using whichever app is currently set as the default Home app, even after a new launcher is installed and opened once.
To change this, open Settings ➔ Apps ➔ Choose default apps ➔ Home app. This screen lists every launcher installed on the device, including One UI and any third-party app. Tap the launcher you want to use and confirm it as the new default.
If the new launcher does not appear in this list, it usually needs an update or has been disabled in the app info. A missing entry is rarely caused by the Home app setting itself.
Switching back works the same way: open the same menu and select Samsung's own launcher again. No data, widgets, or icons from the previous launcher are deleted during the switch, they simply stop being displayed until you switch back.

