For your consideration (although many of you probably have already read it). In my view the best if the cyclical history sci fi novels - although it is not circular history. Relevant to those issues relating to “over and over again” in BSG. (I am confident RDM is well familiar with the book.)
It is post apoctalypic and discusses issues involving church and state. Do not let that latter aspect deter you.
Miller wrote it (in 3 parts for a sci fi magazine) and it was published as a novel (his only one - although another of sorts was published after his death don’t bother with it) in 1960. It won the Hugo in 1961 for best sci if novel. Miller later committed suicide.
Best of all - it is extremely well written - a delight to read.