I've been vaguely aware of the religion for a while, but I'd like to ask some questions about the specifics Unitarian Universalist teachings.

Looking at the movements that lead to the creation of the Unitarian Universalist church, I'm not really sure on the extent to which tradition is followed or the church follows any certain creed. Unitarians believed that God is one all-powerful person, and Universalists believed that all humans will be saved after death. However, neither of these beliefs are part of the church's seven principles. Are there additional teachings of the church outside of the seven principles? To what degree are Unitarianism and Universalism required to consider oneself a Unitarian Universalist?

The UUA website says that while the roots of Unitarian Universalism are Protestant, the modern church isn't really a kind of Christianity at all. Was there some kind of shift away from Christian teachings as a core part of the church? Do most Unitarian Universalists today engage with Christianity, even if it isn't mandated or required? Do practitioners believe that Jesus died so that our sins may be forgiven?

I know these are a lot of questions, and I greatly appreciate any response from the UU community.