I've been binge-reading a ton of Byzantine Empire history books (I just got done reading The Last Centuries of Byzantium by Donald Nicol which was fantastic) and I'm really interested now in learning more in-depth about the Latin Empire. I can't seem to find any books online about it though, I only really have it's Wikipedia page to turn to which is disappointing :(
In English, unfortunately no, there really hasn’t been a lot written about the Latin Empire. The most recent one is:
Filip Van Tricht, The Latin Renovatio of Byzantium: The Empire of Constantinople (1204-1228) (Brill, 2011)
This is really only about the first half of the Empire’s existence. After 1228 it was mostly reduced to the area around Constantinople, and was surrounded by Bulgaria and the remnants of the Byzantine Empire in Nicaea and Epirus. But still, it lasted for another 30 years or so. For more about the years following 1228, another recent book is:
Guy Perry, John of Brienne: King of Jerusalem, Emperor of Constantinople, c. 1175-1237 (Cambridge University Press, 2016)
This is a biography of the emperor John, and not exactly a history of the Empire, although it does have a lot of contextual information about the Empire as well.
Another good one is:
Peter Lock, The Franks in the Aegean, 1204–1500 (Longman, 1995)
However, this is mostly about the crusader states in Greece. Theoretically they were all subject to Constantinople…but not really in practise. There are some chapters about the Empire as well, so it's still very useful.
For some older sources, there is:
Kenneth Setton, The Papacy and the Levant, 1204-1571, vol 1: The Thirteenth and Fourteenth Centuries (American Philosophical Society, 1976)
I mention this mostly for the sake of completeness. A generous review of this book would be “difficult to read”. I remember reading a pretty scathing review of it once…actually it would probably have been better if I didn’t mention it, haha.
Also pretty old, but the classic account in the big “Wisconsin History” of the crusades, is:
Robert L. Wolff, “The Latin Empire of Constantinople, 1204-1261”, in A History of the Crusades, vol 2: The Later Crusades, 1189-1311, ed. Robert L. Wolff and Harry W. Hazard (University of Wisconsin Press, 1969), pp. 186-233
There is also the chapter in the New Cambridge Medieval History:
David Jacoby, "Byzantium after the Fourth Crusade: The Latin Empire of Constantinople and the Frankish States in Greece," in The New Cambridge Medieval History, vol. 5, c. 1198-c. 1300, ed. David Abulafia (Cambridge, 1999)
More has been written about the Latin Empire in French, Italian, and Greek, but I’m not sure if those would be accessible to you. I should at least mention one in French, although it's very old now as well:
Jean Longnon, L’Empire Latin de Constantinople et la Principauté de Moreé (Payot, 1949)
I hope that helps! I would stick with Van Tricht, Perry, and Lock for the best, most up-to-date sources in English.