“Xi is more right than wrong.
He, or Trump, are both absolutely correct.”
Utter nonsense.
Your own recitation of vassal state status refutes your initial statement.
Korea was never part of China.
Korea was, though, part of Japan for a time.
“Korea was never part of China.”
Sure it was. Goes back to the Han dynasty, and over and over since. Look it up.
You can start here -
https://en.wikipedia.org/wiki/Four_Commanderies_of_Han