I can give you my Gluetun+QBittorrent compose file, but I use it with Wireguard.

Once you are in the qbittorrent webUI make sure to bind it to the VPN port, which should be tun0.

services:
  gluetun:
    image: qmcgaw/gluetun
    container_name: qbittorrent_vpn
    cap_add:
      - NET_ADMIN
    environment:
      - VPN_SERVICE_PROVIDER=
      - VPN_TYPE=wireguard
      - WIREGUARD_PRIVATE_KEY==
      - WIREGUARD_ADDRESSES=
      - SERVER_COUNTRIES=
      - TZ=Europe/Prague
    ports:
      - 8080:8080
      - 6881:6881
      - 6881:6881/udp
    restart: unless-stopped
    networks:
      - traefik

  qbittorrent:
    image: lscr.io/linuxserver/qbittorrent:latest
    container_name: qbittorrent
    environment:
      - TZ=Europe/Prague
      - WEBUI_PORT=8080
    volumes:
      - /docker/containers/qbittorrent/config:/config
      - /docker/containers/qbittorrent/downloads:/downloads
    restart: unless-stopped
    network_mode: "service:gluetun"

networks:
  traefik:
    external: true