That's going too far, I think. Sure, you can run your own VPN server, on an anonymously leased and managed VPS. But then, how do you anonymously lease and manage that VPS? As far as I know, your options are pretty much limited to VPN services, Tor and I2P. Also, VPS traffic is readily logged by providers, so your "anonymity" is pretty fragile.
Your best bet is distributing trust among multiple parties, such that no one of them can compromise you. VPN use is common, so start with nested VPN chains. Then Tor. If either the VPN chain or Tor resists compromise, then you're still safe.
After that, you can use any PM or email that you like. Because it's not connected to your meatspace identity. If content is end-to-end encrypted, the provider has nothing useful to share with adversaries. You and correspondents must, of course, avoid leaking metadata through account names and subject lines.
Your best bet is distributing trust among multiple parties, such that no one of them can compromise you. VPN use is common, so start with nested VPN chains. Then Tor. If either the VPN chain or Tor resists compromise, then you're still safe.
After that, you can use any PM or email that you like. Because it's not connected to your meatspace identity. If content is end-to-end encrypted, the provider has nothing useful to share with adversaries. You and correspondents must, of course, avoid leaking metadata through account names and subject lines.