It is all simple. After the collapse of the Soviet Union, Russia never gave up on imperialism, which is at its cultural DNA and at the core of its strategic culture since the 15th century. Russia invaded Transnistria in 1992 and is occupying it to this day. In 1996, the First Chechen War was the first attempt to recapture the breakaway republic of Chechnya. In 1999, Russia finished what it started in Chechnya.
This is how Grozny, the capital city of Chechnya, looked like when Russia was done with it:
After Russia had reconquered Chechnya, it installed Ahmad Kadyrov, the father of Chechnya's current leader Ramzan Kadyrov as its warlord.
In 2008, Russia attacked Georgia and defeated it in an a week-long war after which parts of Georgia, South Ossetia and Abkhazia came under Russian control via puppets installed by Russia.
In 2014, Russian intelligence services organized an insurgency in the Ukrainian regions of Donetsk and Luhansk and sent its military to take control of Crimea, while the Ukrainian military, in disarray at the time, was unable to do much about it at the time.
That started a low-intensity war in eastern Ukraine.
In 2015, Russia assisted the Al-Assad regime of Syria by bombing the rebel-controlled city of Aleppo into ruins.
The Russian mercenary company Wagner has participated in many operations in Sub-Saharan Africa selling its services to local dictators in exchange for mineral reserves.
On February 24 2022, Russia launched a large-scale invasion of Ukraine with the aim of destroying Ukraine as a state and as a nation. The goal was to make that happen in three days. That obviously failed.
The question is now whether the West should support Ukraine with all the humanitarian, financial and lethal aid it needs. Is this "fanning the flames of war"? If you ask the Ukrainians, they are not interested in peace at this time because they know any ceasefire would only be temporary and Russia has a long track record of violating them. Russia's goal of destroying the Ukrainian state and nation has not changed at all.
A ceasefire now would allow Russia time to reconstitute its military after the substantial losses it has suffered during the past year and continue the war when it is ready. The only way to long-term peace is for Ukraine to be supported with everything it needs until Russia is defeated on the battlefield. That would likely lead to internal pressure in Russia sufficient to cause a power struggle within the elites and the ouster of Putin. A period of internal weakness like the 1990s would likely follow giving Eastern Europe and the world at a large a few decades of freedom from a credible treat to peace from Russia. An optimist might dare hope that this could be the last time Russia tries to conquer and destroy its western neighbors due to the ongoing demographic collapse of Russia, which is greatly exacerbated by this war.
If Russia is allowed to conquer and destroy Ukraine not only would that be a gigantic humanitarian disaster of a magnitude last seen in Europe during WW 2, but, even worse, Russia would not stop at Ukraine. It has already made threats on Moldova. Russian propaganda has demonized its neighbors for years. Russia's long-term goal is the restoration of the power of the Russian Empire.
Remember, before the Russian invasion of Ukraine last year, Putin demanded that "NATO withdraw" from all of former Soviet sphere of interest in Eastern and Eastern Central Europe, whatever hell that means.
In my opinion, the Russians are out of their minds. It is true that, historically, Russia whose heartlands are located in the Eastern European plain without natural borders, has been very vulnerable to invasions. This is why Russia has developed a strategic culture aiming at expanding Russia's borders as far from the heartland as possible. But the idea that Russia would be able to regain control of its former Soviet sphere of influence with only half the population and a fraction of its industrial base, is completely unrealistic. Also, the fact that Russia has a massive strategic nuclear arsenal and a doctrine that says Russia will use it if its existence is threatened, makes building such a buffer zone utterly unnecessary. Russia is not under any existential threat from any external actor. Thus the claims that Russia's security concerns have been outrageously ignored by the West are completely baseless.
The Ukrainian nation rejects Russian vassalhood. Russia has legally recognized Ukraine and its 1991 borders. Russia's actions are nothing but a naked 18th century style imperialistic land grab.
The way such behavior should be dealt with is to arm the victim of aggressive imperialism adequately for it to fend off the aggressor and beat it back to its own territory, which interests precisely no one as an object of conquest.
The Russians are not going to start a global thermonuclear war should they prove unable to keep any piece of Ukrainian land they've stolen. The Russian elites are not suicidal. They have their money and children in the West.
And in any case, there is no way the world can give into nuclear blackmail. If that happened, every single tin pot dictator would be trying to acquire nuclear weapons, forcing everyone else who does not already have them or is not a member of a military alliance having them to acquire them themselves. Good luck with the entire Middle East and all other troubled corners of the world being filled with nuclear-armed rogue states.
Great powers lose wars all the time without resorting to nuclear annihilation of everyone including themselves. The West and its allies should continue on the path of supporting Ukraine until all of its lands are liberated. Russia should only be welcomed to the fold of civilized nations when it has undergone self-examination and adjusted its strategic culture to match 21st century realities.