Hi, garmin users affected by the bug of bluetooth instability (ver. 13.21) and conseguent impossibility to configure data screens via app, I've casually discovered a partial solution, that allow you to enter and modify the settings of an activity.
From the watch run the activity you want to configure on your phone and keep it that way, open garmin connect click on the watch icon on top, then press "current activity" than you can enter the settings of the currently running activity on the watch. Repeat the process for every sport you need to set up. I know it's a little bit tricky but it's the only way i've found right now.
If your watch isn't connected with bluetooth to the phone immediately after launching an activity just wait a minute untill the bluetooth works again.
Hope this will work also for you.