He clearly knew that he wouldn't be able to catch up in this life and might be the same in his next life, yet he still went up to challenge him. He was not respecting himself or Yuan Zhou.
Paul was determined not to do that. However, if he could watch Yuan Zhou cook more, he might be able to gain some insight from it. For example, when he saw the superb cutting skills earlier, Paul had comprehended something from them. He felt that he had become more transparent, but he did not have a specific direction. He already had a vague idea, which was a great harvest.
A Challenge Maniac like Paul challenged different chefs almost every day. Even if the chef wasn't famous, as long as he had a skill, he would challenge it. He wasn't obsessed with winning or losing, but his cooking skills improved through the challenge process.