An invasion of Taiwan would dwarf even the plans for Operation Downfall that the US would have implemented before the Atomic bombs and the Soviet declaration of war made it moot.

Plus defending beach heads is actually easier today then it was then thanks to short range ballistic missiles and cruise missiles. Invading Taiwan would be a mess for China and they know it. They’re waiting for the exact right time to take that step and I’m sure the CCP would prefer for the KMT to take back full power there and hopefully adopt a two systems, one nation plan like they had with Hong Kong and Macau.