You can only retire a device using Android Enterprise Work Profile. This is by design. A device using Work Profile is per definition a personal device. A retire of this device would delete the Work Profile in place, while at the same time allowing the user to keep app personal data untouched. Also in this scenario the user will have his privacy protected.
Regarding iOS if you actually use what is called User Enrollement for iOS with a federated apple id, you would see the same issue. Only retire would be possible, not a full device wipe.