The person who gains the most is Xi. It is becoming increasingly obvious that independent Taiwan is a dead man walking. When Xi makes his move wouldn’t it be grand if the only power that could challenge his moves was bogged down in a rapidly escalating quagmire half a world away? A brilliant move on Xi’s part, if responsible. He would have personalized the conflict among all involved and introduced another new low, assassination. Regardless of who’s responsible, this is another major rung up the escalatory process.
Perhaps Xi is trying to destabilize Russia so China can get a more favorable government.
Taiwan, ie the Republic of China, to give it its official name.
The RoC is on an island, is wealthy and heavily armed.
The PRC has no chance of conquering it today. Maybe in a few decades, but not today.