How to configure federation ID and fediverse ID?

#1

I have installed Nextcloud on a subdomain like nc.domain.tld, so the federation id is user@nc.domain.tld and for fediverse @user@nc.domain.tld.

How can i setup it to user@domain.tld and @user@doman.tld?

#2

AFAIK this is not possible. See also this related discussion for Mastodon: