Impossible to install apps on Edge 520 with the Connect IQ mobile app

My Edge 520 never popped up in the IQ app (latest iOS Version) and so i deleted the IQ and Connect App and ignored the Edge 520 in Bluetooth settings.

1. Reinstalled the IQ app and logged in > my Edge 520 is now shown up as not connected in my devices.
2. Paired the Edge with the mobile phone > the 520 is still shown as not connected.

3. Reinstalled the Garmin Connect App > the 520 connects to the phone but instantly vanishes from the IQ app/devices.

Deleting the Garmin Connect App and the Edge will appear again within the IQ app as an unpaired device…

this is strange and it's completely impossible now to install any app on an Edge 520 device since there is no webstore anymore.