it sounds like they rm -rf-ed their project. How would Ctrl+Z help here?

No, your VPN provider needs to offer port forwarding for that to work. You can still use qbittorrent without port forwarding, but it’ll be harder to find peers which could lower your speeds

AFAIK the selling point of gluetun is that the traffic from e.g. a qbittorrent container is guaranteed to go through the VPN - this is also what one would need port forwarding for