It's not a straightforward answer. Different comics handle their races differently. Sometimes Flash wins, sometimes it's a close call, and sometimes Superman might come out on top. It all depends on the writer's imagination and the plot requirements.
Well, it depends on the specific comic and the context. Sometimes Flash is depicted as having an edge in speed, but Superman can also surprise with his own abilities and strategies.
Chapter 462, "I Will Definitely Be a Good Captain!", is the clearest early answer because it turns Good Captain's situation into a concrete plot event. It opens with Inside the practice room, Tai Fan had been staring blankly with the... and closes on He was meant to be dead weight!.
Chapter 392, "Connected to Shang Shaobai", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event.
Chapter 431, "Su Yinwan Is Here Too?!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with [Holy shit, why is Su Yinwan on this show too???] [!!!
Chapter 380, "From today on, you no longer need to work here", is the clearest early answer because it turns Yu Tiantian's situation into a concrete plot event. The chapter turns that into something concrete by moving from Seeing the sudden change in the manager's attitude, everyone around...
Chapter 345, "Audition: She Couldn't Have Gotten in Through Backdoor Connections, Could She?", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 639, "Young Master Gu, Does Your Family Need a Dog?", is the clearest early answer because it turns Jiang Cheng's situation into a concrete plot event. It opens with Half an hour later, Jiang Li pushed open the door and walked out.
Chapter 637, "Does President Shang Know That His Own Family Is Already Bankrupt?", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 520, "Was Zheng Xun Replaced?!", is the clearest early answer because it turns Zhao Lang's situation into a concrete plot event. It opens with What did it mean that Jin Siyue had already given him all the shares?!
Chapter 820, "He’s actually even harder to coax than Buchen!", is the clearest early answer because it turns Buchen's situation into a concrete plot event. It opens with Today, he was particularly cautious with his eating, even sipping his...
Chapter 596, "Then Blow Them All Up", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event. The chapter turns that into something concrete by moving from Jiang Li shook his head without any expression.