As someone that worked in the Former Soviet Union for many years, is married to a Russian and has family members still in Russian, here are a few observations:
Ukraine is far from being a free and democratic state. In fact, it is one of the most corrupt countries on earth, right up there with Russia and Nigeria (which I also worked for many years). In no way, though, am I justifying Putin's invasion. Rather, I am simply pointing out that support for Ukraine should be for humanitarian reasons and not some utopian idea that the west is protecting democracy.
Putin has used the excuse of "liberating" ethnic Russians from other FSU states to stage invasions. Look no further than Georgia in 2014. Given the fact that Stalin dispersed various ethnic groups (including Russians) throughout the FSU, you can bet this won't be last attempt annex other regions. One area to keep an eye on is Transnistria, a semi-autonomous in eastern Moldoa bordering on Ukraine. Transnistria is the Donbas of Moldova and in-fighting has been going on there for years. ... but you never hear about it
While Putin may have his eyes on recreating the FSU, make no mistake, this is about money. Many of Russia's oil and gas pipelines pass through Ukraine on their way to Europe and, in turn, Ukraine receives about $2B per year in tariffs.
Early in Putin's reign, many Russians viewed him much like Reagen with respect to restoring national respect and honor. Now, not so much.
This is a very complicated and doesn't lend itself to simple solutions.