It would be in Russia's interest to have stable, predictable neighbours. There would be no reason for Russia to not step in or invite outside influence to settle the region. Central Asia being stable is pretty much top of the list for both Russia and China. Neither wants regime changes where the US can insert puppets or influence compradores. Unfortunately even stable (for China and Russia) leaders often lead political groups that yield to US influence through one means or another. Western powers would be interested in destabilising partner/traditional allied nations to Russia and China. Russia and China can do no such thing to the west and at least for China, has never tried except idiots believing they can buy some influence with donations.