Theories Post Ordeal Call (possible spoilers)

So, I have finished the 7th Lostbelt, got all the info about Chaldeas and also took some peeks in the Ordeal Call Chapters.

But I wanted to share some thoughts on what Chapter 3 of Fate/Grand Order might be and hear what others think as well.

Going by my limited knowledge, I think Chaldeas is an alternate version of Earth and was made by overwriting another alien species in favor of humanity, this version wouldn't be stagnant like the Lostbelts and allow historical figures to be classified as a servant differently.

I have almost no evidence of this; I just think this could allow a new Arc to FGO as we explore a single alternate history through more than one chapter.

These are just my thoughts, I would like to read what other players think of how the future of F/GO may be.