You can speak freely in anonymous and encrypted channels e.g a matrix server on I2P/TOR, a signal group (just don't use your name), simplex, retroshare over I2P, etc. Telegram is not encrypted!
Just search for "piracy $channel" e.g "piracy I2P chat", "piracy simplex chat", "piracy signal chat", or something similar and you'll find something. There might even be a forum hosted on TOR or I2P if the piracy community is that motivated.
But always remember not to give too many details about yourself. Being anonymous isn't just a technical requirement, it also required personal effort. Tech can't do everything for you.