The battles in Kingdom are not that interesting anymore, it started to decrease in quality after Kanki's death. I was disappointed with the Hango arc and didn't expect much from the Qin - Han war.
I also don't like the theory of Tou marrying Princess Nei from some fans on reddit, maybe Tou is now around 60 years old or more. This marriage, if it really happened, instead of bringing long-term friendship and making it easier for Qin to rule the Han territory after the war, it would be a slap in the face to the Han royal family, I doubt Ei Sei wants to humiliate the defeated enemy and create more trouble for the future.