Take a look at those defeats (you left some off, both external and internal). Why do you think they were so hell bent on building a buffer between themselves and those who have inflicted the vast majority of those defeats? Take a look at the deterioration of the Russian position vis a vis NATO since 1991.
Imagine Trump’s reaction if, in 2017, Putin’s installed puppet, the new socialist president of Mexico, announced that Mexico was becoming the Warsaw Pact’s 30th member (Britain and France being numbers 28 and 29). What might Trump have done? It’s a mirror image of the predicament Putin found himself in. Remember, most of the new NATO members had the boot heel of a murderous 70 year Soviet reign of terror squarely on their necks 35 years ago. Putin is a very dangerous, cornered and guilty as hell animal. The Russians aren’t going to just lay down and allow that last domino to fall. The idiots DC are going to blunder us into WWIII playing world policeman again.
They were hell bent on building an empire. That was the open goal of Peter the Great, of Elizabeth and Catherine, of Alexander I, Nicholas I, etc and etc. No “buffer” involved. Consider the reasons for, say, the war of 1877.
After 1991 Nato nearly collapsed. Budgets were cut, US troops were steadily removed - compare what the US had there in say 1989 vs today - and readiness was nil. Putin has single handedly revived Nato. You are crediting Russian propaganda, absurdly.
To all its neighbors Russia has always been extremely dangerous, whether it was called the USSR or not.
The Mexicans have the equivalent of ten divisions on our border, thanks to the cartels.