Did this work ? I'm trying a similar thing to scale deployment based on AWS MSK consumer group but even after Admin role to keda operator it it still throwing errors:

Warning  KEDAScalerFailed    17m (x6 over 20m)    keda-operator  error getting metadata: kafka.(*Client).Metadata: unexpected EOF

Warning  FailedGetExternalMetric       9s (x80 over 20m)   horizontal-pod-autoscaler  unable to get external metric sowct/s0-kafka-breach_data_n_s/&LabelSelector{MatchLabels:map[string]string{scaledobject.keda.sh/name: kso,},MatchExpressions:[]LabelSelectorRequirement{},}: unable to fetch metrics from external metrics API: rpc error: code = Unknown desc = error when getting metric values metric:s0-kafka-breach_data_n_s encountered error