But even then the implication of some global cutoff year after which certain actions are officially no longer "ethical" or "advisable" is pretty ridiculous. Our ethical standards shouldn't vary only by what year it is, but rather ideally by the broadest possible context we are able to fathom. Israel is a unique case with indigenous jews returning to their native land after unparalleled delay, except in terms of borders modern-day israel doesn't perfectly map to ancient judea, and the crazy history of british intervention, geopolitical tension, war, expansion, and attempted peace treaties.
Also, harming civilians is the norm in modern world. Russia absolutely deliberately is targeting critical civilian infra in Ukraine (e.g. grid during cold winter).
If the Russians also do it, that is additional evidence of war crimes.
war crimes usually defined by intent: were civilians targeted intentionally.
With this in mind, I don't follow your example at all. Are those bankers of wartime value? And if they are, is the collateral damage proportional to that value? It's possible there's a lot I don't know about those banker's links to military!
I'm not sure all the facts are in yet in relation to Ukraine, but I do not anticipate that Putin will be getting his yacht back in the immediate future.
The question was specifically about genocide allegations, and blind trust in UN sub-orgs reports.