Ukraine

Russia currently has 6.5% inflation with 15% interest rate. The only reason the economy is not falling is massive government spending and that is based on oil money. As soon as you remove that Russia has to make really hard economic choices and it seems like they are increasing anti protest units right now. We have seen what happend with Wagner. More armed men in the country and an unhappy population makes Putins collapse more likely. Having problems at the front even more so and Russian losses are very high right now, if Ukranian figures are somewhat accurate.

Thats just what happens with dictatorships. They cover up small problems until there are enough of them and they have a massive crisis. Democracies have small problems talk about them and that avoids massive crisis for the most part. However it is hard to tell what caused the collapse in the end as it always has multiple reasons.