Isolationism depends, I'd reckon, on how the war is seen in retrospect, and may have more to do with the twenties than the war itself.
In OTL, apart from a few poets, the general mass of the population only started looking at the war as a defeat for civilization, on all sides, during the post war slump, when it started to seem that the war had saved nothing.
As a Brit, looking at the hundred days, won the war and lost the peace seems to sum it up.
Greater American involvement in the war wouldn't change that, but greater involvement in the post war politics might- active participation in the League of Nations might have done a lot to save something from the war.
Depends on domestic American politics of the time, I know a bit but not that much. A bloody shambles of a war would likely increase isolationism; a victory would have the opposite effect maybe.
Russia, though, depends on timing- the revolution was due to happen since 1905, and the Tsarist regime's best chance of avoiding it was keeping the population happy with economic growth, which was not happening-
but a faster defeat of Germany means Russia might hold together a little longer, probably still come apart in the post war slump- but with a much stronger regime not committed to war, and with allies not actively at war, and in a better position to intervene.