One similar read could be the 'Horus Heresy' series. It has a lot of the same elements of a dark and complex universe filled with epic battles. Another could be the 'Gaunt's Ghosts' series which also delves into the military aspects and the overall 40k universe. And there's also the 'Eisenhorn' series which is great for those who like a more detective - style story set within the 40k world.
There are several novels that might appeal if you liked 'Plague Wars 40k Novel'. For example, the 'Ultramarines' series. This series focuses on the Ultramarines chapter, one of the most well - known in the Warhammer 40k universe. It has great stories about their battles, their leadership, and their values. Another option is the 'Necromunda' series. It offers a different perspective as it is set in the underhive of a large hive city. But it still has the gritty, violent, and complex nature that 'Plague Wars 40k Novel' has.