Installing update to Ventura 13.1

The " Owner Account of this computer "  has that privilege to add, remove, upgrade or downgrade accounts. This would include adding more Admin Accounts and / or downgrading an ADDED Admin account 

Set up users, guests, and groups on Mac

Normally the " Owner Account  " is the very first Account used when the Computer was Very First Setup as New and out of the box.

Adding additional Admin Account can be done there after.

Below link all provide additional insights about the Difference between Admin Accounts and Owner Accounts  

https://eclecticlight.co/2021/07/18/last-week-on-my-mac-the-perils-of-m1-ownership/

EDITED

catrionaw46 wrote:

When I press restart, I get the message: Passcode is not set. An error occurred while installing the selected updates. Automatic updates is enabled, but so far it has failed to install.

hmmm...

Try from a Safeboot and compare your results:

How to use safe mode on your Mac - Apple Support

I see more on "passcode"—

Activation Lock helps keep your Mac secure, even if it's lost or stolen, and can improve your chances of recovering it. With Activation Lock, your Apple ID password or device passcode is required before anyone can turn off Find My, erase your Mac, or reactivate and use your Mac

Activation Lock for Mac - Apple Support

Activation Lock for Mac - Apple Support

How to remove Activation Lock - Apple Support

How to remove Activation Lock - Apple Support

if no insight or resolve—

Call Customer Support (800) MY–APPLE (800–692–7753)

or on line Apple Support

Outside the USA—Contact Apple for support and service by phone

See a list of Apple phone numbers around the world.

Contact Apple for support and service - Apple Support