Catalonia, the Basque region, Ireland, etc are not comparable to Taiwan. Taiwan _is_ a separate country today already. There is no separatist movement. It’s all just Chinese propaganda. (Officially Taiwan has similar claims, but they clearly have stopped actually exercising them hence that fact isn’t really relevant).

If you want a more accurate comparison it would would be as if Spain started claiming that Portugal is a part of its territory and pushing the world to accept that position.