If you’re willing to take a punt on a new project then take a look at my post history. I’m working on a fully self contained voice/text/screen share web app that has end to end encrypted DMs built in. The only identifying information it asks for during new account setup is an email address for activation (in an effort to prevent bots) but you can disable that during server setup, have your users sign up with fake email addresses and just manage their accounts manually using the built in tools. It doesn’t store IP addresses at all and all the voice/screen share streams are only stored server side long enough to provide a buffer (about 3 seconds worth).