I also know both Russians and Ukrainians. The sane Russians with at least some wealth have mostly left Russia, for good. The ones I know who have stayed (or returned!) are nutjobs; I'm not concerned about the wealthier Russians who haven't left. And as for the poor ones, if they want to live the onus is on them to do something useful like sabotage to make their country lose faster. It's not that hard.

We should not sacrifice the lives of Ukrainians – and quite possibly ourselves in the future – for the sake of Russians.

The fact is, you do in fact win wars by killing the other side more efficiently. WW2 was won because far more Germans and Japanese died than westerners. We were damn good at killing them, to the point where they simply surrendered essentially unconditionally.