The problem with what you are trying to imply here, is that being an "ethnic Russian" doesn't inherently mean that you are bound to be of Russian nationality, and even if you are, that you want to be a citizen and supporter of Russian state.
There are plenty of US citizens who are "ethnic English", yet most of them don't seem like huge fans of the king of England, nor want him to be sovereign over the lands they live on.
If things worked like that, you would think England's special military operation of 1812 would have went much better than it historically did.
For example, you have probably heard of the raids into Russia around Belogrod and so on. Those are being done by people who are not only ethnic Russians, but they are even Russian citizens,
who you could consider rebels against the government in Moscow, and as such helping Ukraine wage war against it.