The demographic situation is manageable, especially given how the generation entering retirement are factory workers, who are being replaced by automation on a massive scale. The generation which enters the labor market has a much higher number of college degrees.
Real estate bubble doesn't concern most Chinese citizens, but only those who used it to speculate, despite being warned by Xi not to[1]. If you own a house for living inside, you don't need to care if its resale value goes up or down. Still, deflating the housing bubble was painful, but China managed to grow the economy through this anyway.
About war, I don't think so, at least not in the next 4 years. Trump and several Republican leaders made it clear already that they don't want to defend Taiwan, so the Taiwanese government will likely refrain from things which could trigger armed conflict. Even if things escalated, a naval blockade would be more likely, and the US public largely doesn't support entering into direct conflict over that[2].
[1] https://www.scmp.com/business/article/2116621/what-president...
[2] https://globalaffairs.org/research/public-opinion-survey/tai...