My experience is based on the android app but it may apply to the IOS app and/or windows program as well.

Problem

The garmin connect app does not install / delete / update watchfaces immediately. It’s not obvious when it does do what the user requests it to do.

Solution

Following seems to work quite reliable:

• go to the display designs view inside the garmin connect app
• execute the desired action (one of following)
  • click on an uninstalled watchface and install it
  • or click on an installed app and click update
  • or click on an installed app and click uninstall
• go back twice to the device view => on top of this view the reload icon starts to spin
• wait for it to finish
• go back to the display designs view and check if the desired action was executed successfully

Sadly, I can’t influence how this works, it’s part of the garmin app and can’t be influenced by me.

Error messages

Currently it seems that you get an error if you want to uninstall a watchface (not just mine, any watchface) - I hope garmin does solve this soon. In the meantime, the workaround above does work as well for me, so please just ignore the ‘displaydesigns’ can not be deleted error dialog and try the solution above.