Both names are good.
The "Yi" in Yipeng means "achievement excellence", and "Peng" represents the big bird in mythology, which means flying high. This name gives people a sense of positivity and success.
The "Yi" in Yi Peng is the marksman in Chinese mythology, symbolizing superb skills and bravery. "Peng" refers to a big bird, symbolizing strength and majesty. This name gives people a brave and determined feeling. Therefore, both Yi Peng and Yi Peng are very good names. The above answers are for reference only, please do not be blindly superstitious.