The OnePlus smartphone can automatically switch to the mobile data if the WiFi connection is poor or fluctuates to ensure the stability of the Internet connection.
The "Intelligent network connection" is disabled by default as the mobile data is accessed, but can be enabled at any time.

Android 10 | OxygenOS 10.0
Step 1:  Open the  Settings
Step 2:  Tap on  Wi-Fi & network
Step 3:  Tap on  Dual-channel network acceleration
Step 4:  Enable or disable  Intelligent network connection
  1. Open the Settings
  2. Tap on Wi-Fi & network
  3. Tap on Dual-channel network acceleration
  4. Enable or disable Intelligent network connection

OnePlus Instructions
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