When russia loses the war with Ukraine, Ukraine will righteously require massive reparations. From where will those come?

From China. China has sufficient US paper holdings to "loan" whatever is required.

What will China require in exchange? Resource extraction rights in all of those formerly Chinese territories, and perhaps more.

Of course, in addition, significant interest and principal must be (re-)paid. Also, China will require the right to station "security forces" in order to protect its operations.

When there is a failure of repayment, or some other artfully constructed phrase from the "loan" agreement serves, China will simply foreclose on its "collateral".

A referendum at that point will almost certainly find many people tired of living under endless russian kleptocracy and desirous, at least, of some prosperity and stability in China.