I am fascinated by that era of history...have you read “Nicholas and Alexandra”? It has a lot of his and “Sunny’s” personal correspondence and is quite insightful.
I’m looking in my library catalog to see if I can find the books I read over the last several years.
One was “The Last Tsar,” by Edvard Radzinsky.
Another was “Alix and Nicky : the passion of the last tsar and tsarina” by Virginia Rounding.