Oppo
Auto-Connect to the Best Wi-Fi Network auf Oppo
When several saved Wi-Fi networks are in range at the same time, ColorOS decides on its own which one carries the connection. This decision comes from a feature called Wi-Fi Assistant, and it runs in the background without asking you first.
The switch usually happens because the phone measures signal strength and picks the network it rates as best at that moment, even mid-session. That can interrupt a video call, pause a download, or briefly disconnect a smart-home app while the new network finishes its handshake.
To change this behavior, open Settings ➔ Wi-Fi ➔ Advanced settings ➔ Wi-Fi Assistant and toggle Auto connect to the best Wi-Fi off. The phone then stays on the network you connected to manually until you switch it yourself.
Leaving the toggle on makes sense in a large house or office with several routers, where staying stuck on a weak signal is more annoying than an occasional automatic switch. If your Wi-Fi trouble is about slow speeds rather than switching, check your router placement or restart the router instead of touching this setting.