I have two comparison shots here of the Viltrox Air vs. the 1.2 GM, both at f/2.0. To me, at least, they look pretty similar. So, the rendering can't be that bad. So I think I'm mostly just missing the f/1.2. On the other hand, it depends so much on subject size, distance, etc. But I don't feel like doing detailed comparisons.
At this distance the Air fits, I think. At this subject distance, I think the Air is a good fit. As I said, I see virtually no image-relevant difference.