Suppose Putin's client is not his own conception of Russian national security, or even public opinion at home but suppose his client is China. Why China? Because China is an enormous threat to Russia and therefore it is understandable that Putin wants to make an ally rather than an invader of China. China offers a huge market for Russian minerals and energy as well as technology trade-offs.
He might believe that China is the wave of the future. He might want to forestall China encroaching on Siberia with its population to simply absorbed Rushias mineral wealth. He might just hold a grudge against the West and especially against America- a little man's inferiority complex that puts a chip on his shoulder. Whatever the motivation, even if it is not in Putin's direct interest as we would calculate it on his behalf, as prudent planners we must assume the worst.
I agree that the greatest threat to Russia is from their east, which makes it an even more of a low odds proposition that they will they will bet their civilization on a westward adventure.