What is best way to secure secret keys with Docker in spring boot application

Recently, started building docker image for my application. Application uses few secret keys which are used to connect other microservices. I read about the docker secrets with swarm mode which hold the application secrets and I made changes in application to accepts the docker secrets. I created secrets using command..

    printf "my-secrets12345" | docker secret create adminpassword

Then I deployed service using following command with docker-compose file..

    version: '3.1'
    services:
      testService:
        secrets:
         - adminpassword
        image: "test-docker-secret:latest"
        #container_name: test-docker-secret
        ports:
         - "8080:8080"
        environment:
          SPRING_PROFILES_ACTIVE: dev
          SERVER_SSL_ENABLED: "true"
        volumes:
         - /home/tridev/pathtocerts/:/tmp/certificates/
    secrets:
      adminpassword:
        external: true

and the deployed

    docker stack deploy --compose-file=test-stack-compose.yml testservice

And all after this my service started and working as expected, Here I thought my secrets are not visible to anyone in plain text and secure now. But when I went inside the container and browsed the directory /run/secrets/, here I can see all my secrets in plain text. Also I can see my secrets from host machine by using

    docker container exec $(docker ps --filter name=testservice -q) cat /run/secrets/adminpassword

Here, I see If anyone get access to my container or service he can see secrets and access data from other services. Here It feels like docker secrets are illusionist and secrets are visible.

Is there any other way with docker where I can store secret keys securely?