Closing apps on watch ultra

Hi swojto,

From what you described in your original post, here is what we recommend: Restart Apple Watch Ultra - Apple Support

*Turn off your Apple Watch Ultra: Press and hold the side button until the sliders appear, tap , then drag the Power Off slider to the right.

*Turn on your Apple Watch Ultra: Hold down the side button until the Apple logo appears.

Note: You can’t restart your Apple Watch Ultra while it’s charging.

The reason why we are recommending the steps above is because you're unable to close apps on your Apple Watch Ultra.

To confirm, are you referring to removing apps from the Dock? If so, then give the steps here a try: Open apps on Apple Watch Ultra - Apple Support

Choose which apps appear in the Dock

You can choose to show the most recently used apps in the Dock or up to 10 of your favorite apps.

•See recently used apps: Open the Settings app  on your Apple Watch Ultra, tap Dock, then tap Recents. The most recently used app appears at the top of the Dock with other apps below, in the order they were last opened.

You can also open the Apple Watch app on your iPhone, tap My Watch, tap Dock, then tap Recents.

•See your favorite apps: Open the Apple Watch app on your iPhone, tap My Watch, then tap Dock. Select Favorites, tap Edit, then tap  next to the apps you want to add. Drag  to adjust their order. Tap Done when you’re finished.

•Remove an app from the Dock: Press the side button, then turn the Digital Crown to the app you want to remove. Swipe left on the app, then tap X.

If the original problem persists after trying the previous steps, please provide us with specifics on what you see for more help, and we will continue from there. 

Thanks for using the Apple Support Communities.

Cheers!