If I'm using a custom server running AWS services, how can I configure my Spring Boot application.yml file to reflect a different host name?

Question

I'm running my own S3 AWS Bucket Service on a custom server. I've added all my environmental variables in my Intellij run configurations. Here's my setup in my application.yml for the local environment. However when I try to use the plugin aws-java-sdk-s3 for example to delete a file from the bucket it still points to s3.Germany.amazonaws.com instead of my internal AWS service.

Here's my application.yml

spring:

  datasource:
    url: ${DATABASE_ADDRESS}
    username: ${DATABASE_USERNAME}
    password: ${DATABASE_PASSWORD}

  cloud:
    aws:
      s3:
        bucket-name: ${AWS_S3_BUCKET_NAME}
        credentials:
          access-key: ${AWS_S3_ACCESS_KEY}
          secret-key: ${AWS_S3_SECRET_KEY}
        hostname: ${AWS_S3_HOSTNAME}
        region:
          static: eu-central-1
          auto: false

  http:
    log-request-details: on

What is the correct syntax for hostname and what other aws errors if any am I making in my application.yml?