I have been using cleanuparr to automate this. I have exes blocked in the download client and then cleanuparr sees they aren’t being downloaded and removes them and triggers another search.

This is a docker compose that I know works for qbittorrent behind gluetun.

I wonder if you are missing the “network_mode: service:gluetun” part?

 qbittorrent:
    image: lscr.io/linuxserver/qbittorrent:latest
    container_name: qbittorrent2
    network_mode: service:gluetun
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Etc/UTC
      - WEBUI_PORT=9090
      - TORRENTING_PORT=6882
    volumes:
      - /path/to/qbittorrent/appdata:/config
      - /mnt/JellyFinContent/Data/torrents:/data/torrents #optional
# ports:
# - 9090:9090
# - 6882:6882
# - 6882:6882/udp
    depends_on:
      gluetun:
        condition: service_healthy
    restart: unless-stopped

Gluetun and mullvad works for sure but, yes, you do need to modify some settings in the compose file. At least I did to get it work.

https://foldingathome.org/

What resources does your qbittorrent have access to? CPU cores / Memory. I have tried running it on a Rpi and it CHUGS so I had to aggressively apply seeding limits and general # of connection limit too.

Setup Trilium and use the Firefox extension to save screenshots or the whole page to it automatically which I love.