If your device is still functional, always try the official over-the-air (OTA) method first before attempting manual flashing.

Oppo has ended major OS updates for the A9 2020. It will not receive Android 12. However, security patches may continue sporadically.

The firmware does a stellar job managing the massive 5000mAh battery. Even after two years, idle drain is minimal (1-2% overnight), and you can easily get 8+ hours of screen-on time with casual use.