When despotic leaders are facing dissention in their own country, they often try to distract their population by rallying them around some nationalistic and racial lies to promote a war abroad.
There is always some actual historical incidents that can legitimately be used to justify grievances of one country about another, usually because of the acts of viciousness carried out by the other country's occupying forces. However, time and newer generations often lead to old animosities dying with those who still harboured them. We just have to look at how Japan and Germany have become an accepted part of the current political and financial world order despite a World War being fought with them not 75 years ago.
In contrast, Eastern European countries were suppressed and excoriated by Russia for decades after the same war, and so their animosities towards Russia have persevered into the newer generations, leading to their continued wariness of Russia. For its part, Russia has always been a pariah in the West because its political system was supposedly against the capitalism and so-called freedom of the West.
Of course, like in China, Communism per se had long been abandoned in favour of plain dictatorship favouring the privileged, who, like the privileged everywhere, corrupt political systems to ensure their wealth and power are maintained, while embedding oppression and poverty into the countries they exploit with the help of those politicians, but also in their own countries.
Such continued egregiousness on the part of corrupt politicians addicted to power produces a lot of dissatisfaction amongst their own citizens. To counter this, politicians will find a lot of scapegoats, whether they be individuals, groups or other countries, to blame for the problems besetting the country and why the politicians are uniquely able to protect the country from their supposedly nefarious influence.
Now, there may be some genuinely dangerous people challenging the country's stability, but they are often used by dictators as justification for suppressing and even torturing and killing anyone who challenges the dictator or their rich supporters, even if those dissidents are pointing out the damaging effects of their corruption and damaging policies. This suppression serves to dissuade others from pursuing similar goals.
When the internal resistance to the dictatorships gets too large, the dictator will likely find some simmering resentment or prejudice against another country as a scapegoat for the country's woes and use it as a pretext to start a war with that country. We saw it in Argentina when the dictators invaded the Falkland Islands on the pretext that they were actually part of Argentina and so many citizens were for the invasion. Now we see it with Russia invading Ukraine on the pretext that they are Nazis persecuting their own Russian-heritage citizens.
However, when Great Britain defended the Falklands, the resulting disappointment in the Argentine population eventually turned towards the dictators who eventually lost control of the country over their suppression and killing of their citizens, even though they still had control of the martial forces of the country. President Putin seems to be in a similar situation as the citizens of Russia find out about his lying about invading Ukraine and the armed forces failure to quickly rout the Ukrainian forces.
I was in the Philippines in the final days of the Marcos regime, where there were mass demonstrations in the streets with one of his generals in attendance, and one of his Presidential Guards told me Marcos' time was over. At some point, even the strongest dictators lose the support of enough of their people that their power evaporates in the face of the dissent of their people.
Often dictators started out as heroes, bringing a new political order to their country, but the autocratic nature of their leadership and the corruption that they used to undermine the previous regime are too addictive to forego to rule on behalf of their people, so they continue the oppression they feigned to oppose so that they, in their turn, can remain in power.
However, the actual power of any human being is quite limited, so any other power is only because a lot of others allow themselves to believe that they actually have it. However, being reliant on others' beliefs is a double-edged sword, and so when that belief is abandoned by enough people, the supposed power is revealed to be merely a figment of peoples' collective imaginations fed by felonious propaganda. It was active for a time but its time ran out!
Many of the institutions people believe in, like countries, money and political systems, are belief pyramid schemes reliant on their participants' continued belief in them. When those beliefs break down, the delusion is broken and whatever that belief was invested in ceases to be important. Archaeology is really the study of the relics of the failed beliefs of previous peoples, trampled on by the new beliefs of those who followed.
Today, Russia is a failed superpower that suffers from the lament of its own loss of meaningful power, but which relies upon its nuclear weapons to remain relevant in a world that has outgrown them. However, the strength of its peoples lives on in the resolve of Ukraine to shake off the remnants of Soviet oppression.
While many in the Western world now take pride in their resolve to bring Russia to heel, hopefully the lesson learned is that all regimes based upon the subjugation of its peoples without allowing them real choice in the direction of their lives will eventually result in their demise. The West has done much to suppress and diminish the aspirations of many peoples around the world, and while they pride themselves on the unity to bolster Ukraine's ability to choose their own future, that unity has much to do to bring the rest of the people on the planet the same true freedoms.