The ups-sidecar should be able to create iOS variants with the data from the associated secrets and write the variant definition (after successful creation) back into the secret. This includes finding a way to identify a iOS variant. For android we use the googleKey, there should be a similar property for iOS.

Have a look here for how it's done for Android: https://github.com/aerogear/ups-config-operator/blob/master/cmd/server/upsClient.go#L19