Can you recommend a title that you really liked? I have to get audiobooks now, because I can’t read very well, but...if I have to grit my teeth and read, I can do it!
Napoleon I re created the military rank of ‘Marshal’ so you can start with reading about Napoleon I Marshals of the First Empire, there were initially 18 of the and the number increased to 26 by the time it was over.
https://en.wikipedia.org/wiki/List_of_Marshals_of_the_First_French_Empire
This is a list and the site has a good bibliography which lists out lots of authors and various books on the marshals as a group and individually. The list is endless if you look at the bibliography of every book you actually DO get. Lots of this stuff you can read on line... enlarge it.
There are many other people who were not at that rank but who also wrote accounts or had accounts written about them. All of them were either close friends, relatives or rivals and the same names will appear in overlapping bio’s. You will be reading a long time.