r2dbc does not work with cloud run

[arscyper007]

Expected Behavior

based on this doc including the cloud-sql connector and setting gcp url as defined below should be working
have tried several variations and it does not connect.
R2DBC URL template: r2dbc:gcp:postgres://<DB_USER>:<DB_PASS>@<CLOUD_SQL_CONNECTION_NAME>/<DATABASE_NAME>

Also have played around with explicitly defining options etc through configuration but no success:
r2dbc:
datasources:
default:
dialect: POSTGRES
username: ${POSTGRES_USER:postgres}
password: ${POSTGRES_PASSWORD:postgres}
schema: postgres
schema-generate: none
url: ${POSTGRES_URL:r2dbc:postgresql://localhost:5433/gcdb}
db-type: postgres
ssl: ${POSTGRES_SSL_ENABLED:false}
options:
driver: pool
protocol: postgresql
acquireRetry: 60
maxSize: ${POSTGRES_POOL_SIZE:2}
minIdle: 1
initialSize: 1
maxIdleTime: PT60M
driver: ${POSTGRES_DRIVER:gcp}

Also tried:

@bean
@singleton
@nAmed("googleConnection")
public ConnectionFactory connectionFactory() {
ConnectionFactoryOptions options = ConnectionFactoryOptions.builder()
.option(DRIVER, "gcp")
.option(PROTOCOL, "postgresql")
.option(PASSWORD, "postgres")
.option(USER, "postgres")
.option(DATABASE, "postgres")
.option(HOST, "project:us-central1:db-instance")
.option(SSL, true)
.option(ENABLE_IAM_AUTH, true)

            .build();

    ConnectionFactory connectionFactory = ConnectionFactories.get(options);
    ConnectionPoolConfiguration poolConfiguration = ConnectionPoolConfiguration.builder(connectionFactory)
            .maxSize(10)
            .maxIdleTime(Duration.ofMinutes(30))
            .build();
    return new ConnectionPool(poolConfiguration);
}

Actual Behaviour

Cannot connect to project:us-central1:db-instance/:5432" it works perfectly fine using the jdbc url with jdbc driver for same container

Steps To Reproduce

No response

Environment Information

JDK17

Example Application

No response

Version

4.1.2