The Xiaomi smartphone can answer calls automatically, and if this feature is enabled, we can set a delay and whether all calls are always accepted automatically, only via Bluetooth or a headset.

Android 10 (MIUI 12.0)
Step 1:  Open the  Phone app
Step 2:  Open the  Settings
Step 3:  Tap on  Auto-answer
Step 4:  Enable or disable  Auto-answer
Step 5:  Choose  Always, Headset only  and/or  Bluetooth only
  1. Open the Phone app
  2. Open the Settings
  3. Tap on Auto-answer
  4. Enable or disable Auto-answer
  5. Choose Always, Headset only and/or Bluetooth only

Xiaomi Instructions