If China intends to take Taiwan and ultimately go beyond that into other parts of Asia, they have a strong interest in having parts of NATO's forces being tied down defending Europe and the Middle East. And vice versa. North Korea will presumably also help to tie down forces in South Korea.
China is not an expansionist imperial power as your comment seems to imply, quite the opposite, it always talks about how they have no intention to expand beyond its borders... but of course, it sees Taiwan as an internal affair (and most other countries in the world acknowledge it and accept its one-China policy). Taiwan was very much a part of China before the Japanese invaded it in 1895 [1] (though it had also been temporarily colonized by European powers before then), and again once the Japanese lost the war in 1945. Taiwan was then controlled by the Republic of China (ROC) "Party". When the civil war ended in 1949, the ROC lost to the Community party in mainland China and millions of its members fled to Taiwan[2] and hoped to later unify China with itself, but that obviously never happened. They continued to claim to be the legitimate government of all of China (and even parts of neighbouring countries), and apparently some of them still do!
From the Wikipedia article:
"The ROC was a founding member of the United Nations, and held the seat of China on the Security Council and other UN bodies until 1971, when it was expelled by Resolution 2758 and replaced with the PRC. Since 1993, the ROC has petitioned the UN for entry, but its applications have not made it past committee stage.[281][282] Due to the One China policy, most UN member states, including the United States, do not wish to discuss the issue of the ROC's political status for fear of souring diplomatic ties with the PRC."
I believe both sides actually want an eventual unification, Taiwan just doesn't want to lose all its autonomy and have a change of political system (it's a democracy, unlike mainland China).
If China can convince Taiwan to democratically rejoin the PRC then that’s fine. If they do it using military force then the issue isn’t really that complicated.
Again, this assumes some kind of overarching relationship among these countries with a shared goal. But what does North Korea gain by, say, keeping South Korea busy while China invades Taiwan? It basically means Pyongyang is flattened by artillery fire and missiles, with a more-likely-than-not chance of regime change.
Taiwan is not a part of NATO. The US may, directly or indirectly, help to defend it, but it is not a military concern for other NATO countries.
But frankly, I find it very difficult to believe it could happen in the near future because Taiwan is already very well prepared for an invasion. So unless the Chinese leaders are as badly informed as the ones from Kremlin, they would not attempt a full-scale war over dead bodies and ruins. They attempt the opposite - to lure the Taiwanese, encourage friendly exchanges etc. A war would completely destroy everything. And I don't believe this is the Chinese aim (yet).
(I don't event mention Chinese loses because they can throw a lot of people and equipment just like Putin did and not care about huge loses.)
> Taiwan is already very well prepared for an invasion
The most likely possibility according to the article is not a direct invasion of Taiwan but China controlling Taiwan's borders so that it can decide what trade gets in and out and what doesn't. I don't think Taiwan is in any position to stop that from happening.
