I guess, that depends on the legislative of your country, maybe they see all interactions with usenet providers as illegal, and if you are not using a VPN they see what IP you talk to. But in the other hand, in such countries, using (foreign) VPNs may also be illegal🤔
Your ISP sees the connection to news.usenetserver.com and if they cared could get a court order to get your data from them. They can compel you to release your username and password.
You also need to protect yourself against future law and enforcement
You can keep secrets from the future. Future decryption won't help government see what you did in the now, the logs don't store the encrypted payload, only the end points and the user/ip