Probably not. The issue is that we can only control one side. So decommissioning requires trust and obviously the current Russia can not be trusted and no Politician would be willing to gamble with the security of people and country if they can just invest money into arms instead. It's the prisoner dilemma with an extremely skewed reward/risk ratio.

The war is directly linked to the cold war, so it's pointless to talk what would have happend if the cold war would have ended differently.

But let's assume the political situation would have been the same and just the stockpile of old soviet weapons was gone: I'd say yes, they would have been just as aggressive in the beginning. After all the didn't really intended to be relying on their old stockpile at the start.

Bud, Russia is aggressive because Putin’s entire rise to power was built on manufactured fear. He likely used FSB agents to execute false flag attacks on Russian citizens and blame it on Chechen separatists. He has had to build on that fear to maintain power, developing a mythological Imperial past that was “stolen” by the west. Conquering Ukraine is the first step in “resurrecting” that glorious fiction. Russia will not stop pursuing this fever dream until Putin and his government are gone - they can’t. It’s basically the only thing keeping them in power. I don’t like wars either, but until we can collectively figure out how to stop these authoritarian impulses there just isn’t any alternative. It’s the paradox of tolerance, essentially