“As far as I am aware, each of these view the others as having valid sacraments and view the moral teachings (how to live) as legitimate. It is the beliefs about God and the Church that are in dispute. NRx, please correct me if I am wrong. “
There is not a uniform understanding of the sacraments. Rome has a differing understanding of grace and the nature of the Church which is very problematic from our POV. The Orthodox Church doesn’t really do the whole “valid” sacraments thing. We refer to sacraments as being with or without grace. And the historic teaching of the Church has been that there are no sacraments outside the Church. Rome has always accepted this, but then turned around and made the teaching meaningless by proposing an invisible church that has no boundaries. Thus from their perspective anyone, including even non-Christians can baptize someone if they use the correct form and matter. This is nonsense from the Orthodox perspective.
Funny how the "two lungs, one church" Catholics don't bother to mention any of this.