I appreciate this as well. Either way, Nextcloud software itself has nothing to do with torrenting or piracy. Ocdownloader will help you torrent by adding a friendly GUI, but you still will need to setup the actual torrenting software (aria2c in their example) yourself.
Second post in the thread is what you must use for privacy: a proxy or VPN to route all your torrenting traffic through. You’ll need to pay a monthly or annual fee for such a service. You’ll also need to set this up manually as well, but thankfully there are tons of guides online. Good luck in getting it going!
All this secures it your connection to Nextcloud via SSL.
All p2p traffic is fully identifiable from your Torrent Client <-> ISP <-> Torrent server
This means anyone interested can follow up with your ISP to complain about what you are torrenting.