Oh, so now the claim is about whether or not Russia can engage on two fronts at once?
Come on! They've already proven that they can't take over even one country even when they were fully staffed and equipped. They've done all they can and have taken massive losses. With whatever they still have left, do you really think they could find another country to invade that is fully equipped and staffed?
Before they even made such an attempt, Russia would have to stop what they're currently doing, call their military home from Ukraine, and do an awful lot of rebuilding of their military before making an attempt on another country.
Also, any country that neighbors Russia should be beefing up their military right now to further reduce any possibility of a Russian invasion. It would make them self-sufficient as opposed to just waiting on the USA to do everything.