Why is my phone not finding an update when it says an update is available?

Earlier today, I got a notification saying that iOS 16.6 on my iPhone 12 is available to install tonight, but I tried to install it earlier.

In Settings, the note appeared for the update.

When the phone was searching for an update, it took longer than usual for an update option to appear, but I get an error stating that no update could be found.

I have restarted and powered off my phone but that still has not done anything.

Maybe I should wait for it to try to automatically install it tonight?