BTC you would “probably” be okay but if you are going full anon i think Monero is the only true anon. im not really into crypto so i dont know how true that is, I just see that mentioned a lot that Monero / XMR is a privacy coin. Cash is king though. Maybe the most annon? frugal usenet and Blocknews actually have a cash payment option on the website at checkout, if you are worried maybe ask them the track record for receiving it. If you are doing VPN to, Mullvad takes cash but you do not need vpn for usenet.

Frugal Usenet vote from me. It has multiple backbones so make sure you set it up correctly in your newsreader (server priorities). there is no provider that doesnt have takedowns. it happens to them all. best to look for reposts if you can.