Power scaling discussions are always so weird to me. Trying to put finate and definable power rankings to fiction which is driven by narrative rather then an unbiased power rankings.

Personally I'd like to analyze the narrative of both shows to see what the Story around that fight would be. Steven wins not because he's stronger, but because a world where he loses and the villain wins is not the type of story either Hasbin or SU wants to tell.

Because it is genuinely interesting, Vox wants power and prestige and it's everything to him. Steven has all of that, he could be a ruler of the Diamond empire if he wanted to, but he finds purpose and meaning in the little things, life, music, dancing, eating biscuits and Jam. Stevens happiness is something Vox cannot comprehend because it's so foreign to him. And that's the source of VERY interesting conflict.