Russia is only isolated from the west (e.g. exports to India are booming) and its internal economy is growing faster than Europe's.

Russia holds leverage over China because China is incredibly resource dependent and very susceptible to the threat of blockade through the first island chain by the US. Only Russia can bypass such a blockade with fertilizer, grain, oil and gas.

The US is driving these countries into each other's arms.

It also works the other way around and I am pretty sure that was what Russia was betting on - with Europe's dependence on Russian energy, Europe would not react strongly to Russia's invasion.

That did not go as expected for Russia either.

It worked until it didn’t. That’s how it goes. Peace is always hard work and irrational actors (in terms of: well being of people, not necessarily aspirations of empire) can muck everything up.

Economical co-dependency is a good tool for increasing the price of going to war and making it irrational. It’s also not a zero sum game and tends to profit both sides. However, it can suck if you do it with non-democratic regimes and autocratic rulers who trample human rights.

So between France, Germany, Poland and all the other EU members it‘s keeping the continent at peace and generally does not suck because it‘s between broadly democratic nations. It also benefits each one massively and makes things possible like a common electric grid that increases reliability in general. So nearly all upside.

I do think economic cooperation with the Soviet Union and later Russia - much, much more limited than between EU members - was helpful in cooling tensions and making the world a bit safer, sure, but Russia has clearly behaved in a way that makes that no longer a good idea.

China is usually seen (I think broadly correctly) as more of a rational actor than Russia. Russia is much more run for the benefit of a weird dictator than run as a country.

Europe was a bit customer for Russia energy, and Russia invaded an EU neighbor nonetheless. After which it stopped being the customer. So it seems like that incentive didn't really work.

Russia did have a big incentive to not antagonize Europe.

But sadly they have a political system that doesn't reflect what is best for the ordinary person. So those incentives can be ignored by those making the decisions.

See also, Trump invading Greenland.

Donbas is mostly wheat fields, Taiwan is mostly SOTA semiconductor fabs that currently are the sole pillar holding up the AI (and compute in general) zeitgeist.

The global response would not be the same, even remotely. And what would China get from it? A tiny island of rubble and an ego boost, while losing enormous global favor? The cost of that island may well be a few trillion for China, just so they can say they defeated the nationalists.

That makes sense, but if that's the case, why aren't they invading Taiwan now? Wouldn't now be the perfect time?

I don't think that mainland China needs any sort of precedent over Taiwan should they decide on military action. The situation is completely different from Ukraine. The South China Sea is also on long-running dispute that predates the PRC (and dates from a time where all the neighbouring countries were Western colonies...) and what has been happening is more a policy of "fait accompli" by occupying unoccupied disputed islands first rather than an "invasion".

I don't know what is the thinking on Ukraine now in Beijing, but they were massively pissed off when Russia invaded because it has caused a lot of disruption to belt and road and to East-West relations in general.