Hot flashes

[Two male leads, time travel, forced love, both are virgins, straight men turned gay]
Zhou Heng, a modern-day salted fish, transmigrates into the body of an unregistered person in a chaotic era, forced into military service on the frontier, and unlocks a mission: assist Xiao Jue in becoming emperor, or face annihilation.
Xiao Jue initially regarded Zhou Heng as a pawn with a bit of cleverness, to be used and discarded.
One night, he stumbled upon someone cornering Zhou Heng in the shadows, his clothes disheveled, tears welling in his eyes. He treated him indifferently, seeing him as merely a subordinate.
But from then on, that fair neck and those frightened eyes haunted his dreams every night.