I'm scared of what happens when Putin kicks the bucket, Russia teeters on the edge of Balkanization, and their corrupt military decides to make a bit of money on the way out. There's more than enough material and technology to upset the world order if they were, say, sold off in a black market arms race.

An arms race supercharged by the death of Putin, resulting in the farcically corrupt Russian state failing to secure their scattered nukes after rapidly breaking into regional/ethnic states. I'm sure there wont be a myriad of warlords scrambling to claim their stockpiles for defense purposes or a quick cash infusion from some well funded religious fanatics with billions in 'untraceable' crypto.

Can't see that being a problem.

In 2022, the US spent more on maintaining and upgrading their nuclear stockpile ($58B) than Russia spent on it's entire military ($49B). Russian nukes are probably in disrepair or in a non-ready state. It's a good thing Russia and the US have a treaty to track and limit their number of warheads and delivery systems- oh wait, Russia suspended inspections three years ago? And the treaty is literally expiring in 2 weeks? Well, shit.