Suppose one is permanently connected to a trusted VPN.
Further let's suppose the primary objective is torrenting solely.
Is there a point to go further, in particular for a proxy?
I ask on behalf of reading mixed information, e.g. for Transmission client:
Proxies don't work, and Transmission Project decided long ago not to give false hope to users (or plain lies, like others do). From a technical point of view, the traffic handled by a bittorrent client is not the kind of traffic you can route through a proxy, not even a Socks5 proxy. The only thing that works is external to the application: a VPN, and also application level routing (which AFAIK is only available on Linux).