Apple has finally released the option to disable your wallpaper and notification in third beta of iOS 16.2 for Always On Display.
Here's how to disable your wallpaper and notifications on iPhone:
You will need an iPhone 14 running iOS 16.2 or later.
Launch the Settings app.
Tap Display & Brightness.
Then Tap Always On Display.
You will then have the option to toggle off "Wallpaper" and "Notifications".
This will give iPhone users the same experience that Android users have with a completely black screen with just the time.