This will not end well...here are the possibilities I see.
1-Russia takes control in all of east Ukraine with little opposition.
2-Russia takes control in all of east Ukraine, the US and EU hit Russia with serious and painful sanctions. Russia retaliates in kind and the result is the end of the Petrodollar and the end of the US dollar as the world’s reserve currency. This results in economic disaster as the dollar collapses and inflation runs wild. Russia dramatically increases the cost of gas to EU countries, they will buy the more expensive gas...Russia makes more money and humiliates the west at the same time. The EU should not have bent to the will of the Greenies..they could have their own gas and not be over a barrel.
3-Russia faces external forces in the Ukraine conflict, either NATO or US forces directly of as a result of an influx of sophisticated western military weaponry. Russia hits western interests economically and or militarily, either might well escalate to a nuclear conflict.
4- Russia backs down and Ukraine joins the EU and eventually NATO. This option will not happen because Russia will not back down on Ukraine.
Scenario 1,2 or 3 will come to pass... there is no other possible outcome.
One thing, Russians can bear a lot of pain. The West, not so much. The U.S., for Ukraine, nothing.
War is just politics. It’s NOT the best military that wins, its the side who can sustain domestic support the longest.