It’s not going any farther than Ukraine because Russia was defeated at Khiv and Kharkiv and exposed as a second rate militarily power. Putin wants no part of a confrontation with NATO. If he ekes out a victory in the reduced theater of the Donbas it will be a hollow victory at a crippling cost to Russian material, lives and his economy. He occupied half the Donbas to begin with prior to the invasion and now as a result he’s united NATO against him, destroyed his economy by catastrophic sanctions, turned his country basically into a surf for China and united NATO against him and brought NATO to his doorstep across twice the border expanse by Finland’s ascension. Not a smart move.