It seems that SMLoginItemSetEnabled() does not work in Ventura (13.0) and register() should be used instead:
To enable or disable LoginItems in macOS 13 and later, use the register() and unregister() methods instead.
Source: https://developer.apple.com/documentation/servicemanagement/1501557-smloginitemsetenabled
On launch, when Yes is hit...

... a failure is shown:
