My insights into the subject of the Soviet Union is just the basics we are learnt in school. Nothing deeper.
I did read the Robert K Massie book, Peter the great. But that is not super relevant.
Also in the process of reading the colossus that is William L Shirer, The Rise and Fall of the Third Reich.
That book goes into alot of detail so it's super long. But nazi Germany only existed 1933-1945 so it's not so many years.
While the CCCP / USSR lasted 1922-1991.
So the time span is much greater. What I am most interested in, is before, during and after the October revolution. Also the first decade or so, how the implementation process was and how the opposition was doing.
So where does one start the study of the Soviet Union?
I am studying Russian history myself and I would recommend 2 excellent books. 1: Russia and the Russians by Hosking (sorry I can't check his first name right now) This book is an overview of Russian history from zero till now. It's very well written and as unbiased as can be found. You could skip to the part about soviet history of course 2: A People's Tragedy by Orlando Figes, is a really detailed history of the Russian revolution, which gives a lot of context as to how and why it happened like it did.