Are there any good auto-biographies, testimonies, or journals of military officers from the age of colonialism? I think it would be cool to read what French or British military officers thought about being deployed to Africa or Afghanistan back in the 1800s. What there daily life was like. The hardships, the adventure, the interactions with locals, the political and strategic situation from their perspective?
You might be interested in the day to day diaries of Lieutenant Watkin Tench, a marine lieutenant who accompanied Australia's First Fleet in 1788 to establish the initial Australian convict settlement. The were published almost immediately as "A Narrative of the Expedition to Botany Bay" and "A Complete Account of the Settlement at Port Jackson".
They have recently been republished as "Watkin Tench's 1788 edited and introduced by Tim Flannery" available here:
https://full-english-books.net/english-books/full-book-watkin-tenchs-1788-read-online