Antonio Giustozzi's War, Politics, and Society in Afghanistan, 1978-1992 is my favorite Afghan-centric history of the period. It discusses how traditional and modern Afghan social structures affected and were affected by the war (especially the urban-rural or center-periphery relationships, which are very salient in Afghanistan). His more recent Empires of Mud covers the role of non-state armed leaders ("warlords") in Afghan society, though Empires extends well after the end of the war. For a complementary and more recent look at warlordism in Afghanistan, Romain Malejacq's Warlord Survival is a good read although it's far more modern in focus. If you're especially curious about the center-periphery mode of analysis, Giustozzi has an article in a 2009 issue of Central Asian Survey which is worth reading (again, not limited to the Soviet-Afghan War. The title is "Centre–periphery relations in Afghanistan: Badakhshan between patrimonialism and institution-building".

For a deeper background of Afghan history before the Soviet invasion, the two books I am going to recommend here are both fairly old actually. Vartan Gregorian's The Emergence of Modern Afghanistan was first published in I believe 1969, but it's still a really titanic book in the space - university courses are taught out of it for instance, and a friend of mine with some significant professional experience dealing with modern Afghanistan has described it as "the kind of book scholars aspire to write once in their life". It explains at a deep level the social, political and cultural evolutions which produced the modernized Afghan state, and honestly I think the fact that it was written before the Soviet invasion affords it some clarity. Louis Dupree's Afghanistan is similarly excellent, although the 1980 edition also has an afterword that discusses the roots of the invasion specifically.

On the Soviet side, my go-to trifecta of accessible English-language sources are Rodric Braithwaite's Afgantsy, Mark Galeotti's Afghanistan: The Soviet Union's Last War, and the English translation of the Soviet General Staff study, published in the West as The Soviet-Afghan War: How a Superpower Fought and Lost. Braithwaite is the best overall history of the progression of the conflict from the Soviet perspective, including discussions of political developments on the home front, the decision-making process that led to the deployment of Soviet forces in the first place, and then of course the decision to terminate the war. Galeotti is more focused on social and cultural factors for the Soviet military; his chapter on demographics and military culture within the Limited Contingent of Soviet Forces in Afghanistan is worth it alone. Mark wrote this book while he was living in Russia in the early 90s, so it both benefits and suffers from that perspective - definitely keep that in mind when you read it. The General Staff study is a dispassionate and professional look at what the Soviets perceived the sources of their loss to be. They had certain blinders on while writing it but it's a very tidy source in general. Just...don't read Les Grau's footnotes. Grau was the translator and he felt the need to editorialize a lot of frankly goofy explanations for aspects of Soviet underperformance, like the inherent low morale of Communist armies.

Finally, looking at things from the perspective of the Americans (who cannot be discounted here), Peter Tomsen's The Wars of Afghanistan: Messianic Terrorism, Tribal Conflicts, and the Failures of Great Powers is decent. Lays a lot of blame on the Pakistani government which is maybe here nor there. Tomsen centers American foreign policy in his analysis, but it's worth reading for that perspective. Steve Coll's Ghost Wars is a pretty detailed look at the murky path of US support to the Afghan mujahedeen groups, although parts of it are totally unverifiable owing to the secretive nature of the topic.