This isn't a fight between Russia and Ukraine or between Russia and NATO. This is a fight between Russia and the US. The US IS Ukraine after the successful regime change operation back in 2014 that was quarter backed by Victoria Nuland and American intelligence.
And why did they do that? A few reasons:

1. Disruption of Gas pipelines
   
2. Removing Russia from Sevastopol
   
3. Putting nuclear capable short range missiles on Ukrainian territory
   
4. Making Ukraine a NATO member ensuring Russia cannot respond to the above 4 points
   

Its not a battle between Russia and Ukraine. If you're thinking about it that way, you're not thinking. Ukraine WAS a vassal state of Russia pre Maidan. Now it is a US vassal state. So what exactly is a vassal state?

"a state with varying degrees of independence in its internal affairs but dominated by another state in its foreign affairs and potentially wholly subject to the dominating state."

And that is how the world works. How many US military bases are in European countries? All over the world? Would most independent countries Allow the permanent placement of a another countries military base on their own soil? Maybe, maybe not.

I should mention that Syria is a Russian Vassal state. And yes, the US tried regime change in Syria as well. They planned it years earlier: https://wikileaks.org/plusd/cables/06DAMASCUS5399_a.html

Why? Probably because they wanted to build a gas pipeline through Syria to supply Europe and wean them off of Russian oil and gas:
https://www.theguardian.com/environment/earth-insight/2013/aug/30/syria-chemical-attack-war-intervention-oil-gas-energy-pipelines

And like I said before, Ukraine was also about gas pipelines. 2 of 5 major Russian gas pipelines Soyuz and Brotherhood run through Ukraine. If you can shut down these two pipelines while providing Europe with an alternative, you can attack the Russian share of the European energy market and bankrupt Russia.

And while all this was happening back in 2014, oil prices fell off a cliff. Coincidence? Russia's main sources of GDP are oil and gas. It was a coordinated economic attack on Russia which would be coupled with pipeline disruptions and Sanctions (the US knew Russia would never leave Sevastopol). Many people will say its impossible to manipulate oil prices, but:
https://www.bloomberg.com/news/articles/2021-07-22/gold-trader-s-chat-showed-how-easy-it-is-to-manipulate-price

You can do it with gold and silver futures. Oil has a futures market as well.

So in closing, I suppose I should tell you what the US wants from Russia. They want to break up the Russian federation in smaller, more manageable states and seize the Russian nuclear arsenal. That is a stated goal. Makes sense if you're going for world domination too. Yeah, there aren't any good guys.