If profit drives Putin, why Ukraine and not another neighbour who hasn’t been courting NATO and accepting western money, weapons, training, etc since at least circa 2014? The answer is because the US chose Ukraine to provoke Russia.
Well, there’s really no reason to use hard power on any country that hasn’t been courting NATO. You can just use soft power (Belarus, Kazakhstan) in that case. Precisely when this ceases to work and a country does starts approaching Russia’s rivals, Russia appears to employ their military power (Moldova, Georgia and Ukraine).