Trump is engaging in a time-honored negotiation strategy of expanding the possible parameters of a deal. He has added the Taiwan issue to the overall china trade and security issues that were already on the table. Now he can make a concession on Taiwan in exchange for Chinese concessions on other issues.
It's a brilliant strategy, but the Chinese are not fools. They feel they already "bought" the one China policy concession from us by not invading Taiwan and exposing how hollow our treaty commitment to defend Taiwan is. They are not likely to let Trump use their own chess pieces against them.
China's big weapon is North Korea. They can ratchet tensions up or down as they need, within limits. Of course, they don't want to go so far as to provoke South Korea and Japan to openly adopt nuclear weapons, but their little Korean friend may have his own ideas. Of course, it helps China's leverage for him to be seen as more or less insane.
I see the potential for a game-changing global deal here. The back and forth bargaining will be a master class in negotiation.