If so, this has got to be making Taiwan nervous...
Not just Taiwan.
IIRC, the real threat to Taiwan is not outright invasion, its an effective economic blockade. Taiwan can’t survive without trade. There need be little or no fighting if the balance of naval and air power, plus the potential for international consequences to China, is such that the threat alone brings Taiwan to terms. Invading Taiwan should be unnecessary.
On the other hand, amphibious landings would be a threat to any state in the region. Vietnam, Malaysia, Brunei, and the Philippines could easily be threatened. The Chinese could use an amphibious invasion annex an island (like Palawan, and numerous others in the Philippines), overthrow a state (like Brunei) or bypass a defense line (like with Vietnam).
What they need most desperately is a fleet of 10-20 very good, modern, diesel/electric AIP submarines.
With the 20 or so large LST type vessels, the three large LPD vessels they have built in the last few years, and now these two LHA large amphibious assault vessels, and with their own submarines and many new frigates and destroyers to protect them, Taiwan would not be able to stop it.
As it is, the ROC has gotten so close to the PRC in terms of their economics, that it is doubtful it will ever come to that. They are simply becoming to dependent economically on the mainland.
No, Japan should be worried—they could land on the disputed Islands or maybe Okanawa? Or maybe Korea! This is a bold step for China but a needed one if they are to become a world power. Japan was once a powerful naval power—but their great ships are rusting on the bottom of the sea.