China will never have a better opportunity to move on Taiwan that now or the near future. Taiwan sees the Trump abandonment coming, and has every incentive to make an attack on the island as costly as possible. The proliferation of defensive firepower via SUAS continues to expand, but Taiwan is highly likely not yet as armed up as they'll need to be. The U.S., through Trump, is as vulnerable to Chinese bribery, chicanery, and leverage as they're ever likely to be before Taiwan becomes too tough to take.
If China is of a mind to forcibly invade and occupy Taiwan, probably the timing doesn't get better than within the next year or so.
Taiwan is a major thorn in their side, and a disproportionate military focus. A successful seizure of Taiwan would allow China to then refocus its military development and posture in whatever was suits them without the need to have so much built around the ability to fight and take Taiwan. I don't know in practical terms what that means, but probably with Taiwan seized, China would be happy to continue building a true blue water navy and basically be a bully throughout Southeast Asia in pursuit of larger economic and political objectives and regional hegemony- 'their hemisphere'. The rest of the world would only stay pissy at them for so long before the need to normalize trade and diplomatic relations in the face of a fait accomplit.