How do I restore missing Apple Watch Complications?

Hi ignaciofromajax

welcome to the Apple (user-to-user) Community!

Re: Apple Watch app missing complications

Am no expert in this area, yet your request deserves some response.

Wondering which Watch OS version is installed on the Watch 6.

Your Watch (and possibly your new iPhone too) may need updating to the newest compatible OS versions.

You can check for iPhone updates in Settings > General > Software updates. if updating:wise to back-up data first

(Eg: About iOS 18 Updates - Apple Support says 18.2 is the latest version)

Updating Watch, if needed:

Apple Support has an article online that may help: See how to: Update your Apple Watch - Apple Support

Eg: You can update your Apple Watch automatically overnight, or manually, using your iPhone

or

If your Apple Watch has watchOS 6 or later, you can install updates without your iPhone:

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Re: "I am also unable to use some of the regular complications such as, Heart Rate, ECG, Oxygen level, Breathe, Weather, Stocks or Activity circles, all these aren’t available for any of my watch faces."

See the latest Watch Face info. (links below) for WatchOS 11:

Eg: Available Complications and more: Apple Watch faces and their features - Apple Support

or

Use iPhone to: Explore the Face Gallery on Apple Watch - Apple Support

Tips on how to: Change the watch face on your Apple Watch - Apple Support

Eg: How to:

"Add complications to the watch face

You can add special features—called complications—to some watch faces, so you can instantly check things like stock prices, the weather report, or information from other apps you installed.

1. With the watch face showing, touch and hold the display, then tap Edit.
2. Swipe left all the way to the end.
3. If a face offers complications, they’re shown on the last screen.
4. Tap a complication to select it, then turn the Digital Crown to choose a new one—Activity or Heart Rate, for example.
5. When you’re finished, press the Digital Crown to save your changes, then tap the face to switch to it."

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Else: If you are already using iPhone with iOS 18.2 and Watch 6 with WatchOS 11, and still need help or support:

You may want to reach out to the Apple Watch Support Team (Online chat / phone / email etc.)

There is a "Get Support - start now" link at the bottom of their website: Apple Watch - Official Apple Support

All the best :-)