Cover art
Weber, Dave, and Jacob Holo. The Gordian Protocol. Baen 2019.

Weber, Dave, and Jacob Holo. The Gordian Protocol
Divergence: 1940 CE
What if: Hitler was assassinated in May 1940, provoking a German civil war that led to the restoration of the German monarchy and peace with Britain and its allies. Subsequently, the West went to war with the Soviet Union in 1945.
Summary: A history professor has a mental breakdown when his memories of the past collide suddenly sharply disagree with the world he is in. And then he becomes involved in the conflict between time travelers from two different 30th Centuries.
Published: Baen 2019 (148148396XBUY).