I mean Taiwan is effectively independent. Everyone knows that. If China want to save face, why not grant that? China never said that they would invade no matter what, right?
Its not an invasion. According to their viewpoint, Taiwan doesn't exist as a nation. Its just another part of China and always has been.
Like US pretend that there is Uyghur genocide, but literally does nothing to prevent it. Because they know that there is no genocide.
Same here, China knows Taiwan is independent, but as long as everyone does not say so, China is perfectly OK to play along.