Ling Lan knew well of the facade Li Lanfeng wore in front of others. Truth be told, Ling Lan also couldn't confirm whether she had actually seen through Li Lanfeng's real personality.
His facade was probably due to the instinct of someone who was adept in strategizing. They would never allow anyone to see their real side so unless it was either a partner they deeply loved or a family member they deeply cared about, the real side of those people would never see the light of day. All those hassles they went through were to avoid their deepest fear, losing control of their destiny, fate, and themselves.
Despite it being a necessary instinct for a competent strategist, the constant pressure they were under, the facade they constantly had to keep up, was very draining for anyone that even the most competent strategist would sometimes succumb to their instincts, unable to distinguish between their true selves and their facade.