Putin has many faults and lots of problems at home. However, over 30 years since the fall of communism and the separation of the Soviet Union, NATO despite promises to Russia has continued to advance Eastward. Now despite Russia declaring it a no go. NATO is openly courting Ukraine. Despite Russia repeatedly wanting limits to NATO set. Russia's concerned were dismissed out of hand. This is very recent. They called for Russia to de escalate while sending arms to Ukraine.
On 22/6/1941 the Nazis invaded Russia through Ukraine, as a result Russia lost up to 28 million people, so foreign forces in Ukraine provokes a larger fear in ordinary Russians, where very few families did not suffer losses in WW2. On top of that the US backed coup in 2014 had a strong neo nazi element which alarmed the Russians, which is reasonable given history.
On the other hand Ukrainians have reasonable resentment of Russians due to the forced famines in the 1920-30s. Significant numbers of Ukrainians welcomed the Nazis in 1941 and helped them throughout. Once given power in 2014 the first laws passed were anti Russian language and culture. Hence we have the Crimea and Donbass situations because both areas are Russia ethnically.
The answer to me is to remove the ultranationalist right wing from the Ukrainian Government and establish a form of neutrality between Russia and Ukraine. First being no NATO. Ukraine is an independent nation but needs to either peacefully let those who want emigrate to Russia or cede the Donbass to Russia.
All this has been stirred up by the US, Ukraine deserves security and so does Russia. My view is get the Yanks the hell out of it. There are many points of argument between Ukraine and Russia, but historically there are many family and social ties. All neighbours have to learn to live together, friendly and respectfully is the best way. That can be achieved if the West keeps out.