When I was a Christian of the liberal stripe I believe that God created the universe.
Did how he did it matter to me?
No.
Big Bang was what science was pointing to at that time, although now the thinking is that that was simply the start of this part of the multiverse so all we have done is push it back a little.
There was no conflict for me with evolution and God.
I had not even heard that such a conflict existed for others - I only heard about YECism after becoming an atheist.
The Bible was written in the main by people trying to explain their interpretation of God. That was obviously filtered through the scientific knowledge of their time.
We now have a better understanding of science. Does that make their insights less valid? It depends what you look at them for. If you look at them for science, then they have zero validity. If you look at them for the idea of the human connecting in some fashion with the divine, then they are as valid today as they were when they were written.
That is my old views, of course. Now I am an atheist it no longer matters to me. But the thing is, it didn't matter to me when I was a christian. Evolutionism did not make me lose my faith - it did not even conflict in any way with my faith.
As to why I believed in God it was because I felt a connection with him and to the person, Jesus, described in the New Testament. Maybe this is what is meant when people talk about it being a relationship.
Now of course I know that there was never anything there except my own wishful thinking.
A question for you, Nick: if evolution was proven to you to be completely true, would you lose faith in God? That seems to be the logical conclusion but it seems odd to me. Salvation hardly rests on belief that the world is young.