Both can be true: Russia can lack numbers to make a strategic breakthrough, and Ukraine can simultaneously not be able to field enough materiel to be able to recapture their losses.
IMO the most likely outcome is a stalemate that turns into de jure conquest of the territory Russia has captured and it turns into a cold (or at least cooler) war.
My friends who grew up outside Oz find it weird that to me “it ain’t Christmas unless it’s scorching hot”. To me the idea of having a cold Christmas is the odd one.