Is it more anonymous to register Njalla by email or XMPP?

I want to use the service Njalla anonymously, but I do not know whether to register by email or XMPP. Email is accessed and managed via the Web via Tor. Please tell me which one is better in terms of privacy and security. Also, please tell me where to create an XMPP account or a recommended provider! !

I have no experience with Njalla, but I guess XMPP might be a bit more private, especially if you access it over Tor, because email is mostly unencrypted between servers while XMPP servers tend to enforce TLS between server to server traffic.

On where to create an account, I guess I would recommend checking compliance.conversations.im and reading about the random servers it offers you.

Should it be done with Tor Browser or an app?