Overall i think korenizatsia there was more justified as they dealt with clearly distinct nations whereas Ukraine was always a grey zone in this regard. It also seems to have been handled better in those cases, but i'm not an expert on this topic. I could be totally wrong, i'm eager to learn more if you have any insights.

I'll just say we have the benefit of hindsight, and if they knew how things would eventually turn out i think the Bolsheviks probably would have opted for an approach more similar to China's policy toward ethnic minorities. However, China is a unitary state and the USSR was a union of republics, very different systems and that fact alone restricts you in the kind of approach that you can take to such issues.