If Russia invades Ukraine, I suspect this is part of an eventual plan by China to take or re-take Taiwan, which it considers a renegade province. The parallels are similar.
Furthermore, Russia knows there is little the US can do about the Ukraine situation, and it doesn’t seem there is all much that could be done about Taiwan, either.
If Russia invades Ukraine, this seems a bit like a trial run for China taking Taiwan.
The U.S. had sole superpower status since World War II. Over the past 20 years, globalization, the US wars in Afghanistan and Iraq, etc, have eroded U.S. stature and power. Economics has also changed – China is now a manufacturing powerhouse. Both China and Russia have modern militaries too.
The 21st century is not going to be like the 20th century.
Note – I have no special knowledge or experience in global issues or international relations. I just make observations and ask stupid questions.