I’m having a service running on Google Kubernetes Engine and would like to access an AWS service using Workforce Identity Federation following this guide

I managed already to get the web Identity Token from my google service account and I also tested with an ubuntu-pod with the aws cli installed that it worked so I am positive that the setup is correct.
However when I try to get the AWS credentials from my java application using the SDK it fails to get them.

Caused by: software.amazon.awssdk.core.exception.SdkClientException: Unable to load 
credentials from any of the providers in the chain 
AwsCredentialsProviderChain(credentialsProviders=[SystemPropertyCredentialsProvider(), 
EnvironmentVariableCredentialsProvider(), WebIdentityTokenCredentialsProvider(), 
ProfileCredentialsProvider(profileName=default, profileFile=ProfileFile(sections=[])),
 ContainerCredentialsProvider(), InstanceProfileCredentialsProvider()]) : 
[SystemPropertyCredentialsProvider(): Unable to load credentials from system settings.
 Access key must be specified either via environment variable (AWS_ACCESS_KEY_ID) or 
system property (aws.accessKeyId)., EnvironmentVariableCredentialsProvider(): Unable to
 load credentials from system settings. Access key must be specified either via 
environment variable (AWS_ACCESS_KEY_ID) or system property (aws.accessKeyId)., 
WebIdentityTokenCredentialsProvider(): Either the environment variable 
AWS_WEB_IDENTITY_TOKEN_FILE or the javaproperty aws.webIdentityTokenFile must be set.,
 ProfileCredentialsProvider(profileName=default, profileFile=ProfileFile(sections=[])):
 Profile file contained no credentials for profile 'default': ProfileFile(sections=[]),
 ContainerCredentialsProvider(): Cannot fetch credentials from container - neither 
AWS_CONTAINER_CREDENTIALS_FULL_URI or AWS_CONTAINER_CREDENTIALS_RELATIVE_URI environment
 variables are set., InstanceProfileCredentialsProvider(): Failed to load credentials 
from IMDS.]

My code is beneath using software.amazon.awssdk:sts:2.26.0:

try (StsClient stsClient = StsClient.builder()
            .region(Region.of(appProperties.getAwsRegion()))
            .build()) {
          AssumeRoleWithWebIdentityRequest request = AssumeRoleWithWebIdentityRequest.builder()
              .roleArn(appProperties.getAwsGoogleRoleArn())
              .roleSessionName(extractSub(idTokenFromMetadataServer))
              .webIdentityToken(idTokenFromMetadataServer)
              .build();
          AssumeRoleWithWebIdentityResponse response = stsClient.assumeRoleWithWebIdentity(
              request);
          String accessKey = credentials().accessKeyId();
          String secretKey = response.credentials().secretAccessKey();
        }

The aws region variable is ‘eu-north-1’