How to reliably bind NymVPN to qBittorrent or other BitTorrent clients?

Pretty self-explanatory. I tried to go the usual “select your VPN’s network interface” route, but what confused me is that NymVPN creates tun0 and tun1 network interfaces. Tun1 was the one that worked, and I selected it. It worked as expected. However, when I looked into why there are two interfaces to begin with, I discovered that they make up a TunTun mode for managing 2-hop communication and figured that using tun1 directly could be wrong. So I’d like some clarity on that: Is it OK to use tun1 for torrenting? Does it negatively affect anything - for example, breaking proper onion routing with traffic not being re-encrypted properly for one node? And what is the proper way to bind NymVPN to torrenting applications such as qBittorrent so that, if I disconnect, their traffic is cut off before it can leak?