There is any number of actions that Russia could have taken to avoid this war.
Or was the question trying to imply that Russia has no agency and can only react? Well, if that's the case, I would disagree. Russia has its goals which it pursues regardless of external circumstances. It may point to those circumstances as excuses, but had they been different, that would just result in different excuses.
In order to not have the shortage of its own white Russian-speaking population, which is the sole reason Russia started this war, Russia could have pursued its own population-growth strategies.
Russia had plenty of warning time to know that its population was shrinking to the point where it would no longer service its territory. The demographic problem was being reported back in 2000s.
People everywhere respond to incentives. People start families when they feel a sense of security about the future and when they can find social support for raising children.
Most of Russia's wealth is concentrated in Moscow. The money flows there through administration of selling of natural resources extracted from the rest of the country.
Had Russia maintained more educational and industrial institutions around the country, it could have subsidized a middle-class lifestyle which would be more conducive to starting families. Instead it elected to allow the Moscow consumerism to dictate its economic decisions.
That meant cutthroat pricing on consumer goods. Essentially everything was outsourced and virtually nothing was produced. So people through out the country lost a sense of hope or purpose.
Which resulted in continued history, and eventually culture, of low birth rates.
For a while, Russia's solution was to keep corrupting Ukrainian politicians to keep Ukraine poor and within its sphere of influence. In 2014, Ukrainians protested for months. Eventually, the Russian puppet fled and Ukrainians elected a pro-Ukrainian politician.
Desperate to keep its source of cheap labor and general population replacement, Russia panicked and staged a laughable attempt at an infiltration.
Ukrainians, shocked by the fact that the so-called "brotherly nation" would send its army against them, simply didn't respond and let Russia take Crimea. Although some more-nationalist units fought back in the East and took back Mariupol, a city Russia also initially captured back then.
Eventually Russia went back to its old strategy of trying to corrupt local politicians and keeping a low-key conflict going in the East in the hopes that NATO would not consider Ukrainian membership because Ukraine was in a territorial conflict.
This strategy had a partial success until Ukraine elected Zelensky, who could be best described as a pot-hole President. He was spending most of his efforts on fixing roads and slowly fighting corruption.
This didn't work for Russia. Russia was hoping to present itself as a better value proposition to Ukraine (as in "we are the ones fixing the roads while your own government is corrupt"). So they invaded.