@dnmaster My solution was to disable IPv6 in qbittorrent. I did not understand the reply from staff, and I disagree that "there is a problem in how I use curl", having a wireguard interface for airvpn is precisely what I am trying to achieve and it works for IPv4 with the configuration I posted. I have limited knowledge when it comes to networking and my setup "just works" for IPv4, I wish someone explained how I need to "set up routes" or something like that.