Ofcourse, these calculations will be more complicated, and affected by geopolitics (It would be hard to sanction or invade Russia more than what was already happening in the cold war, and while both nations had nuclear weapons) I don't mean exclusively invasions, for example, war with china would be ridiculous right now. But sanctioning it for the xinjang genocide would be a good start. Also countering its global influence and buying out people they're trying to influence, espionage maybe?
I agree in the 40s, Nazi germany was the first priority, not only because of its expansionism but its entire ideology was explicitly racist. To counter the holodomor, I think it would be interesting to think about other countermeasures. For example when the soviets tried to blockade West Berlin, the allies put together an emergency operation to air drop supplied in to west germany so they didn't starve. Stalin did not want to shoot down the american planes because he didn't want war either. (This was called the
Berlin Airlift.)
I think the most moral thing for the holodomor would be to organise a similar airlift to drop food by air on the areas identified in Ukraine, probably make base this operation in the black sea and funnel things through Turkey or Germany again.
With regards to the Kristalnacht behaviour in Israel Palestine - It is already very obviously a genocidal occupation there, and Israel has acted expansionist in many wars before, and even suppresed the more egalitarian Palestine Liberation Organisation and for christ's sake, palestinians and arab israeli citizens living in Israel actually have less rights than jewish citizens - essentially segregation based on race.
The most moral thing for that would be to reduce all money and weapons from the West/US to Israel. If Israel would not give up at that point, I would also try to see if the PLO can be re-established and support them with as much aid and weapons as possible. If they gave up on their genocidal behaviour (unlikely considering how the polls you can see coming out of Israel about their views on palestinians; their only pro-palestinian party is like 0.01% of their electorate or something?)maybe a reintegratery period, maybe something like a Mandate of a larger nation or coalition of nations whose main aim would be reintegration and prevention of genocide. Tensions are so high that diversification is needed extremely quickly and perhaps ask any of the people who want to leave give them a free pass out of there or economically incentivise that even. I do not think forced expulsion of israelis would be a good idea considering the backlash that would have, but if they're willing to stay and live in an equal society with palestinians that would be great.
If you get what I mean? I don't want just invasions all the time, but whatever gets the best results and acted upon the best intelligence.