The keyboard on the OnePlus smartphone not only includes an auto-correction but also a spell checker that can be turned on/off independently at any time.

Wrongly spelled words are not corrected immediately, but only underlined to draw attention to a typo.

Android 10 | OxygenOS 10.0
Spell check -  Open the  Settings
Spell check -  Tap on  System
Spell check -  Tap on  Languages & input
Spell check -  Tap on  Virtual keyboard
Spell check -  Tap on  Gboard
Spell check -  Tap on  Text correction
Spell check -  Enable or disable  Spell check
  1. Open the Settings
  2. Tap on System
  3. Tap on Languages & input
  4. Tap on Virtual keyboard
  5. Tap on Gboard
  6. Tap on Text correction
  7. Enable or disable Spell check

OnePlus Instructions