Cannot disable cloud platform autodiscovery

I’m running on GCP’s GKE and I’m blocking access to metadata server ( by using GlobalNetworkPolicy as I don’t want pods to be able to interact with it.
Looking at the logs of the istio-proxy sidecar I see that it is trying to interact with the metadata server to discover on which platform it is running on and because metadata server access is blocked it delays the time it takes the istio-proxy container to be ready significantly (over 2 minutes):

2022-04-26T08:44:07.103224Z	info	FLAG: --concurrency="2"
2022-04-26T08:44:07.103255Z	info	FLAG: --domain="test.svc.cluster.local"
2022-04-26T08:44:07.103264Z	info	FLAG: --help="false"
2022-04-26T08:44:07.103269Z	info	FLAG: --log_as_json="false"
2022-04-26T08:44:07.103273Z	info	FLAG: --log_caller=""
2022-04-26T08:44:07.103278Z	info	FLAG: --log_output_level="default:info"
2022-04-26T08:44:07.103282Z	info	FLAG: --log_rotate=""
2022-04-26T08:44:07.103287Z	info	FLAG: --log_rotate_max_age="30"
2022-04-26T08:44:07.103292Z	info	FLAG: --log_rotate_max_backups="1000"
2022-04-26T08:44:07.103297Z	info	FLAG: --log_rotate_max_size="104857600"
2022-04-26T08:44:07.103302Z	info	FLAG: --log_stacktrace_level="default:none"
2022-04-26T08:44:07.103329Z	info	FLAG: --log_target="[stdout]"
2022-04-26T08:44:07.103335Z	info	FLAG: --meshConfig="./etc/istio/config/mesh"
2022-04-26T08:44:07.103340Z	info	FLAG: --outlierLogPath=""
2022-04-26T08:44:07.103366Z	info	FLAG: --proxyComponentLogLevel="misc:error"
2022-04-26T08:44:07.103372Z	info	FLAG: --proxyLogLevel="warning"
2022-04-26T08:44:07.103377Z	info	FLAG: --serviceCluster="istio-proxy"
2022-04-26T08:44:07.103381Z	info	FLAG: --stsPort="0"
2022-04-26T08:44:07.103385Z	info	FLAG: --templateFile=""
2022-04-26T08:44:07.103390Z	info	FLAG: --tokenManagerPlugin="GoogleTokenExchange"
2022-04-26T08:44:07.103397Z	info	FLAG: --vklog="0"
2022-04-26T08:44:07.103403Z	info	Version 1.13.3-b28579cb30c12c428ea58279b7c06f3302abe924-Clean
2022-04-26T08:44:07.103627Z	info	Proxy role	ips=[] type=sidecar id=test-0.test domain=test.svc.cluster.local
2022-04-26T08:44:07.103790Z	info	Apply proxy config from env {}

2022-04-26T08:44:07.105562Z	info	Effective config: binaryPath: /usr/local/bin/envoy
concurrency: 2
configPath: ./etc/istio/proxy
controlPlaneAuthPolicy: MUTUAL_TLS
discoveryAddress: istiod.istio-system.svc:15012
drainDuration: 45s
parentShutdownDuration: 60s
proxyAdminPort: 15000
serviceCluster: istio-proxy
statNameLength: 189
statusPort: 15020
terminationDrainDuration: 5s
    address: zipkin.istio-system:9411

2022-04-26T08:44:07.105588Z	info	JWT policy is third-party-jwt
2022-04-26T08:44:07.124377Z	info	platform detected is GCP
2022-04-26T08:44:07.124575Z	info	CA Endpoint istiod.istio-system.svc:15012, provider Citadel
2022-04-26T08:44:07.124617Z	info	Using CA istiod.istio-system.svc:15012 cert with certs: var/run/secrets/istio/root-cert.pem
2022-04-26T08:44:07.124802Z	info	citadelclient	Citadel client using custom root cert: var/run/secrets/istio/root-cert.pem
2022-04-26T08:44:07.127847Z	info	Opening status port 15020
2022-04-26T08:44:07.162681Z	info	ads	All caches have been synced up in 68.84646ms, marking server ready
2022-04-26T08:44:07.163031Z	info	sds	SDS server for workload certificates started, listening on "etc/istio/proxy/SDS"
2022-04-26T08:44:07.163076Z	info	xdsproxy	Initializing with upstream address "istiod.istio-system.svc:15012" and cluster "Kubernetes"
2022-04-26T08:44:07.168975Z	info	sds	Starting SDS grpc server
2022-04-26T08:44:07.169103Z	info	starting Http service at
2022-04-26T08:44:07.206685Z	error	error in getting aws info for iam/info : Get "": context deadline exceeded (Client.Timeout exceeded while awaiting headers)
2022-04-26T08:44:07.445829Z	info	cache	generated new workload certificate	latency=281.597604ms ttl=23h59m59.554188773s
2022-04-26T08:44:07.445877Z	info	cache	Root cert has changed, start rotating root cert
2022-04-26T08:44:07.445902Z	info	ads	XDS: Incremental Pushing:0 ConnectedEndpoints:0 Version:
2022-04-26T08:44:07.445970Z	info	cache	returned workload trust anchor from cache	ttl=23h59m59.554034003s
2022-04-26T08:46:21.950914Z	warn	Error fetching GCP zone: Get "": dial tcp i/o timeout
2022-04-26T08:46:35.671510Z	warn	Error fetching GCP zone: Get "": dial tcp i/o timeout
2022-04-26T08:46:35.671560Z	info	Pilot SAN: [istiod.istio-system.svc]
2022-04-26T08:46:35.673749Z	info	Starting proxy agent
2022-04-26T08:46:35.673945Z	info	Epoch 0 starting
2022-04-26T08:46:35.674101Z	info	Envoy command: [-c etc/istio/proxy/envoy-rev0.json --restart-epoch 0 --drain-time-s 45 --drain-strategy immediate --parent-shutdown-time-s 60 --local-address-ip-version v4 --file-flush-interval-msec 1000 --disable-hot-restart --log-format %Y-%m-%dT%T.%fZ	%l	envoy %n	%v -l warning --component-log-level misc:error --concurrency 2]
2022-04-26T08:46:35.768721Z	info	xdsproxy	connected to upstream XDS server: istiod.istio-system.svc:15012
2022-04-26T08:46:35.815383Z	info	ads	ADS: new connection for node:test-0.test-1
2022-04-26T08:46:35.815527Z	info	cache	returned workload trust anchor from cache	ttl=23h57m31.184482382s
2022-04-26T08:46:35.816077Z	info	ads	SDS: PUSH request for node:test-0.test resources:1 size:1.1kB resource:ROOTCA
2022-04-26T08:46:35.855430Z	info	ads	ADS: new connection for node:test-0.test-2
2022-04-26T08:46:35.856000Z	info	cache	returned workload certificate from cache	ttl=23h57m31.144015711s
2022-04-26T08:46:35.856481Z	info	ads	SDS: PUSH request for node:test-0.test resources:1 size:4.0kB resource:default
2022-04-26T08:46:36.155029Z	info	Readiness succeeded in 2m29.059840508s
2022-04-26T08:46:36.155640Z	info	Envoy proxy is ready

How can I instruct the istio-proxy sidecar to skip the cloud platform discovery step?
And generally asking - why is this step required to begin with? (why does it needs to know on which cloud platform it is running on?)

I tried to set the CLOUD_PLATFORM environment variable on the istiod pod to none but it didn’t seem to have any affect.

Please advise.