passwords have disappeared out of settings since new update

Apple has made it easier for you.

Instead of tapping Settings and then scrolling down to find Passwords and tapping to open........

Simply tap on the Passwords App on your home screen. You might want to move the app to your "main" screen if it is now on the 3rd or 4th page.

You're right, it's no longer in Settings. Use the Passwords app that came with iOS 18.