Apple 7 watch second hand

Choose a watch face that keeps it on all the time;

Explore the Face Gallery on Apple Watch

I don’t have Series 7 or Ultra handy to check, but Series 5 and 6 don’t display the second hand when the display is running at lower power; when your arm is not lifted. They will update the display once per minute, when always-on is selected. But not the seconds.

Background details on this: Use the Always On feature with your Apple Watch - Apple Support

Log feedback: Feedback - Watch - Apple