You can disable the wallpaper and notifications on the most recent beta version of iOS 16

Apple has introduced new functionality to the always-on display feature offered for the iPhone 14 Pro models with the third beta of iOS 16.2 that was made available to developers this morning.
When the always-on display option is selected, there are now two toggles for turning off the wallpaper and notifications. Open the Settings app, choose Display & Brightness, and then navigate to the Always On Display section to access the choices.

If you have always-on display enabled, turning off your wallpaper will erase it, and turning off your notifications will stop them from appearing, leaving only the clock and any widgets you may have put on your Lock Screen.

For those who want a more simplistic appearance and might potentially save some battery life, the revised option offers a more simpler always-on display interface.