Why invade when you can buy & bribe your way into control?
You invade you break things. The Chinese want hegemony not physical occupation. Physical occupation is so last century. The Chinese want a form of colonization where they reap the commercial benefits and bought-off “round eyes” do all the grubby governing stuff.
And what kind of idiot wants to make the Chinese even more powerful by wishing for ChiCom control of Siberia? A neocon idiot?