Due to the one child policy, China is going to experience a demographic collapse this decade as more people retire than are available to replace them in the workforce. So the 2020s is the pivotal decade as China nears the height of its power. The CCP is aware of this and knows that if they are ever going to take Taiwan, it would ideally be this decade. Politically, it will also need a victory as the Chinese economy inevitably slows down due to the demographic collapse.
I fear that if the CCP manages to take Kinmen island without a devastating US response then it will be the Austria moment of our century. Obviously, a strong US response would be damaging to both countries, but the only way to deter an attack on Taiwan is to make the cost of attacking so high for the CCP that it is not worth it. While it will be difficult to justify in the short term, the US must push back strongly when China is "testing the waters" or else it will only escalate from there. If there is only a weak US response, it will embolden the CCP to continue pushing the boundaries until they do something that requires either full scale war or surrender (such as invasion of Taiwan main island).