Turn off OLED display after boot / restart

Only this, from the link I posted above:

  • priority ( Optional , float): The priority to execute your custom initialization code. A higher value means a high priority and thus also your code being executed earlier. Please note this is an ESPhome-internal value and any change will not be marked as a breaking change. Defaults to -10 . Priorities (you can use any value between them too):
  • 800.0 : This is where all hardware initialization of vital components is executed. For example setting switches to their initial state.
  • 600.0 : This is where most sensors are set up.
  • 250.0 : At this priority, WiFi is initialized.
  • 200.0 : Network connections like MQTT/native API are set up at this priority.
  • -100.0 : At this priority, pretty much everything should already be initialized.

You could power it from a GPIO that is LOW on boot and only send the pin high when you need it. See the table lover down on this page: ESP32 Pinout Reference: Which GPIO pins should you use? | Random Nerd Tutorials

You may need a switching transistor if the pin is not able to supply enough current.