Samsung
Forget a Saved Wi-Fi Network auf Samsung
Every Wi-Fi network your Samsung device has ever joined stays saved in the connection list, even after you move away or no longer need it. The phone keeps scanning for these stored networks whenever Wi-Fi is turned on, which can slow down how fast it locks onto a network that is actually in range.
Removing an old entry clears this background search and can also fix issues where the phone auto-connects to a weak or outdated network instead of a better one nearby.
To remove a saved network, go to Settings ➔ Connections ➔ Wi-Fi, open the Menu, then tap Advanced ➔ Manage networks. Select the saved network you want to remove and tap Forget.
This only deletes the saved profile and password. It does not affect the router itself, and you can rejoin the same network later by entering the password again. If you plan to reconnect soon, changing the network priority instead of forgetting it can be the better option.