The notion of risk rely on probability of the danger to occur. Think about a massive meteor crossing Earth’s path. It might be the end of life on Earth, so it’s a overwhelming danger. But it’s very unlikely, so the risk is very low. On the other side, the risk of getting a cold in winter is pretty high, but the danger is very low.
I would advice you to use Gluetun instead of crude Wireguard. Within gluetun you just have to set the port for the qbittorrent’s gui to be accessible locally, and open docker’s firewall for qbittorrent. Then set qbittorrent container to use Gluetun’s network.