The tags are wrong: this is not a dual male-lead story!!!
[Fast-paced, quick transmigration, TV and film worlds, each world is standalone, one-on-one romance or flying solo, male leads are hopeless romantics]
World One: The Long Season (Complete), gender-swapped Wang Yang x Fu Weijun
World Two: Constantine (Complete), original character Li Li x John Constantine
World Three: Coraline (animated film) (Complete), original character wolf girl x anthropomorphic black cat
World Four: The Haunted Cop Shop + The Haunted School (Complete), original character Qian Xia x Kam Muk-Kei
World Five: Goodbye Mr. Loser (Complete), gender-swapped, universally adored Da Chun
World Six: Romance of Our Parents (Complete), transmigrates into Jiang Dehua's body x gender-swapped An Xin
World Seven: Door Lock (Complete), Scumbag Reform System x Zheng Fei and Xiao Wu, no CP, one-sided crushes
Don't be scared by the gender change. After reading it, I found that the writing is very good, the emotions are very delicate, and the plot is reasonable. The "Long Season" chapter is very good, and the fanfics of the show can be ranked in the top 3.