Occasionally, it does no harm to restart the OnePlus smartphone, as this will clear the system cache, close apps in the background and complete any new installations of apps or updates.
A restart cleans up the system and often resolves system errors caused by overlapping cache files.

Android 10 | OxygenOS 10.0
Restart -  Press and hold the  power button
Restart -  Tap on  Restart
  1. Press and hold the power button
  2. Tap on Restart

OnePlus Instructions