The Chinese government's top priority is the supremacy of the party. They will invade Taiwan no matter what kind of economic damage it would do, if they believe it will strengthen Xi and the party in the long run.
No country would be stupid enough to bring all that crashing down because some stupid nationalist dispute in the Balkans, that would be idiotic and stupid. Clearly people are to rational for that.
If you’re betting on human rationality over time in the hands of people with a lot of centralized power, you’re making the losing bet. There’s a reason people were genuinely afraid of nuclear war (and still should continue to be): if it happens, it will involve very few people and there will be nothing any one of the billion’s of others can do about it.
There is a solution: the dispersal of power tends to work well; but the risk you run up against is charismatic individuals acting as a locus for a majority’s power, so you also need anti-majoritarian institutions and a culture that values them. Hard to get all three.
Futher the Ottomans were the ones who attacked Russia first, after the war had already gone on several months.
Russian involvement with Germany had almost nothing to do with Eastern European political ambitions and everything to do with the treaty between Russia and France guarenteeing Russia's protection of France in the event of conflict with Germany. Russia only got involved, not out of a desire to beat down Austria-Hungry but to protect Serbia, which had an implicit promise of protection from Russia, against the Austro-Hungarians.
Russia's only major gain from the great war was ever going to be the squashing of German power before it could challenge Russia in the East, and turned out to be the biggest mistake in Russian history.
https://history.stackexchange.com/questions/35758/why-did-ru...
World leaders are generally logical within the bounds of their incentives -- and China's incentives are probably such that an invasion of Taiwan makes more sense to them than it does to outside observers.
But even if it did... did Putin think that there would be no sanctions? Did he think that Finland and Sweden would not see this as their cue to join NATO? Did he think that the rest of the world would just sit there and ignore it?
That is what makes it a bad idea. Almost everyone expected Russia to win quickly. But even if they did win, all the things you mentioned would offset whatever they would gain from their victory.
Putin was probably hoping that the EU would not be willing to go without Russian gas after the war had ended -- and maybe that would have been true, but there would still be other sanctions, other countries joining NATO, etc.
Xi cracked down on SV-type of tech. Which isn't useful tech. It's ad and addiction tech that is a net negative to society. It makes a few people filthy rich but does nothing for the productive basis of your country.
From what I read the crackdown was temporary and is now coming to an end. I guess they've achieved whatever goals were pursued and it is back to business as usual.
https://www.cnn.com/2023/01/09/economy/china-economy-guo-shu...