Are Xi'an and Zhengzhou on the same level?

Yes.

According to China Economic Data, the GDP of Xi'an and Zhengzhou have both exceeded one trillion, and they are both cities in the "trillion club", but Zhengzhou is slightly higher than Xi'an.

Xi'an and Zhengzhou are both in the north of my country and are the "new first-tier cities" in the north. Xi'an is the capital of Shaanxi Province and Zhengzhou is the capital of Henan Province. Both are "national central cities".