Improve my actual docker backup system

Question

I've a personal documentation/git environment running on vmware.
I'm actually making manual backup on an offline media with Duplicati (that I love!)
I backup the entire virtual machine folder! And i feel like I could do better by simply backupping the volumes. I'm using a debian. This is my actual composer

version: "3"
services:
  db:
      image: postgres
      restart: always
      environment:
       - "POSTGRES_USER=User"
       - "POSTGRES_PASSWORD=Password"
       - "POSTGRES_DB=Database"
      volumes:
       - /home/user/Docker/Volumes/db_data:/var/lib/postgresql/data
       - /home/user/Docker/Documentazione/docker_postgres_init.sql:/docker-entrypoint-initdb.d/docker_postgres_init.sql
      networks:
       - docs

  git:
      image: gogs/gogs:latest
      restart: always
      ports:
       - "11022:22"
       - "11080:3000"
      links:
       - db
      environment:
       - "RUN_CROND=true"
      networks:
       - docs
      volumes:
       - /home/user/Docker/Volumes/gogs_data:/data
      depends_on:
       - db

  wiki:
      image: requarks/wiki:2
      depends_on:
       - db
      environment:
        DB_TYPE: postgres
        DB_HOST: db
        DB_PORT: 5432
        DB_USER: some_user
        DB_PASS: some_pass
        DB_NAME: the_db_name
      restart: always
      networks:
       - docs
      links:
       - db
      ports:
        - "11081:3000"
  kanban:
    image: ghcr.io/plankanban/planka:latest
    command: >
      bash -c
        "for i in `seq 1 30`; do
          ./start.sh &&
          s=$$? && break || s=$$?;
          echo \"Tried $$i times. Waiting 5 seconds...\";
          sleep 5;
        done; (exit $$s)"
    restart: always
    volumes:
      - /home/user/Docker/Volumes/user_avatars:/app/public/user-avatars
      - /home/user/Docker/Volumes/project_background_images:/app/public/project-background-images
      - /home/user/Docker/Volumes/attachments:/app/private/attachments
    ports:
      - 11082:1337
    networks:
       - docs
    links:
       - db
    environment:
      - BASE_URL=http://kanban.casa
      - TRUST_PROXY=0
      - DATABASE_URL=postgresql://a_strange_user:with_a_strange_password@db/planka
      - SECRET_KEY="SuperSecretKey"
    depends_on:
      - db

  proxy:
    image: 'jc21/nginx-proxy-manager:latest'
    restart: always
    ports:
      - '80:80' # Public HTTP Port
      - '443:443' # Public HTTPS Port
      - '81:81' # Admin Web Port
    depends_on:
      - db
      - wiki
      - git
      - kanban
    networks:
      - docs
    links:
      - db
    volumes:
      - /home/user/Docker/Volumes/proxy_manager_data:/data
      - /home/user/Docker/Volumes/proxy_manager_letsencrypt:/etc/letsencrypt

networks:
    docs:
      driver: bridge 

I've spent almost a full week to have this working! Hence, I'm no expert at all.
I like the setup and I'm happy with the output, but I'm not totally satisfied with my backup system. First of all I think it is not reliable, in term of availability, I've this offline storage I write things in that could fails. And I'm not feeling certain of a backup restore from a virtual machine folder (I always stop the VM before starting the Duplicati backup).

Is there a better way to have the volumes elsewhere, like in a cloud? I could manage to spend few bucks for peace of mind, but as of my backups, I like security, everything on the remote should be encrypted, communication should be secure, etc. etc.

What is the best practice?

Thanks