I doubt your using NixOS so this config might seem useless but at its core it is a simple systemd timer service and bash scripting.

To convert this to another OS you will use cron to call the script at the time you want. Copy the part between script="" and then change out variables like the location of where docker-compose is stored since its different on NixOS.

Let me explain the script. We start out by defining the backupDate variable, this will be the name of the zip file. As of now that variable would be 2023-07-12. We then go to each folder with a docker-compose.yml file and take it down. You could also replace down with stop if you don't plan on updating each night like I do. I use rclone to connect to Dropbox but rclone supports many providers so check it out and see if it has the one you need. Lastly I use rclone to connect to my Dropbox and delete anything older than 7 days in the backup folder. If you end up going my route and get stuck let me know and I can help out. Good luck.

systemd = {
      timers.docker-backup = {
        wantedBy = [ "timers.target" ];
        partOf = [ "docker-backup.service" ];
        timerConfig.OnCalendar= "*-*-* 3:30:00";
      };
      services.docker-backup = {
        serviceConfig.Type = "oneshot";
        serviceConfig.User = "root";
        script = ''
        backupDate=$(date  +'%F')
        cd /docker/apps/rss
        ${pkgs.docker-compose}/bin/docker-compose down

        cd /docker/apps/paaster
        ${pkgs.docker-compose}/bin/docker-compose down

        cd /docker/no-backup-apps/nextcloud
        ${pkgs.docker-compose}/bin/docker-compose down

        cd /docker/apps/nginx-proxy-manager
        ${pkgs.docker-compose}/bin/docker-compose down

        cd /docker/backups/
        ${pkgs.zip}/bin/zip -r server-backup-$backupDate.zip /docker/apps

        cd /docker/apps/nginx-proxy-manager
        ${pkgs.docker-compose}/bin/docker-compose pull
        ${pkgs.docker-compose}/bin/docker-compose up -d

        cd /docker/apps/paaster
        ${pkgs.docker-compose}/bin/docker-compose pull
        ${pkgs.docker-compose}/bin/docker-compose up -d

        cd /docker/apps/rss
        ${pkgs.docker-compose}/bin/docker-compose pull
        ${pkgs.docker-compose}/bin/docker-compose up -d

        cd /docker/no-backup-apps/nextcloud
        ${pkgs.docker-compose}/bin/docker-compose pull
        ${pkgs.docker-compose}/bin/docker-compose up -d

        cd /docker/backups/
        ${pkgs.rclone}/bin/rclone copy server-backup-$backupDate.zip Dropbox:Server-Backup/
        rm server-backup-$backupDate.zip
        ${pkgs.rclone}/bin/rclone delete --min-age 7d Dropbox:Server-Backup/
        '';
      };
    };