Ukraine may be a poor nation if you just look at the GDP per capita, but it is a nation rich in natural resources like mineral wealth and agricultural land, which is the breadbasket of Europe.  Ukraine has 30% of the world's richest black soil.  Ukraine even exports agricultural products like corn to China.

The educational level of Ukrainians is high, and the country has a significant industrialized base.  Compared to Russia, Ukraine has great weather and was a tourist hub along the Black Sea even during Soviet times.  The famous tourist resort Yalta, next to the Black Sea in the Crimea, which Russia annexed in 2014, just whetted Putin's appetite for more military conquests with no permanent debilitating sanctions from the west.

Frankly, without Ukraine, Russia, climate-wise, is too far north, even though it is rich in oil and natural gas and other minerals.  Russia will never become a self-sufficient power player on the world stage without Ukraine to feed it.  Russia may have nuclear weapons to scare nations, but it has no chance of becoming a world-respected economic powerhouse if it can't feed itself.

If Russia gets a monopoly on gas and oil exports to Europe through the pipeline and an agricultural monopoly with control over Ukraine, then Europe could be extorted at some point in the future.  Russia could extort some kind of military demands from NATO or preferential trade deals with Europe.  Putin will no longer be alive if that happens, but whoever takes over the rule of Russia could be in the driver's seat as far as future European politics goes.

I give the odds of Ukraine being invaded partially or fully at over 50 percent since ignorant Biden has already withdrawn American military advisers from Ukraine, but this may be just a rumor, since I couldn't locate any printed validity, and there are military advisers in Taiwan.  Estonia and Latvia have sent military hardware to Ukraine because they sincerely believe that if Ukraine falls, then the Baltic States may be next to be annexed even though they are members of NATO.  Ice-free sea ports on the Baltic are Putin's temptation.

If Russia invades Ukraine, then I further make a prediction that Finland with its border with Russia and Sweden will also want to join NATO to "guarantee" a non-invasion by Russia.  Sweden may also join NATO.

If Putin has the courage to invade Ukraine militarily, then copycat Xi Jinping could make a military move on Taiwan during the weak Biden administration, too.

Who will benefit in the long run from tyrant military adventures?  The military industrial complex, which will have new reasons to ask for an increase in its budget.

Tyrants are dangerous when they feel that their power is threatened, and COVID has made Putin and Xi Jinping a little more restless due to public dissatisfaction with the way the pandemic was handled among other reasons.  Tyrants have a tendency to try to win a military conflict to enhance their waning prestige among the common folk.  Military success has a tendency to at least temporarily increase nationalistic feelings of solidarity with the regime in power.

Why do I have a slightly pessimistic view about tyrants?  Because tyrants respect only stronger military force, since their power stems from forcing their citizens to obey at the point of a gun and not through other forms of voluntary persuasion.  In a nutshell, tyrants can act immorally or unethically and can't be trusted, so they fail miserably as humans you can coexist with peacefully.  It is a scary coexistence because you can't respect and trust that their promises or contractual agreements will not be broken.

So Putin wants to invade Ukraine, but I don't know how desperately he wants to do so.  Crimea was invaded during the Obama administration, when Biden was vice president.  Ukraine may be invaded during Biden's presidency, and if this happens, then Biden will go down as the worst president in United States history.