What makes you think they're having "such a hard time?" Their advance on Kiev is outpacing the US's advance on Baghdad by leaps and bounds. Most of the claimed losses and wins by both sides are propaganda, with much more coming from the Ukrainian side while the Russians are keeping mostly quiet. There are some facts that seem fairly solid, like the defenders at Snake Island having surrendered, but even that's hard to tell with all the fog of war. It'll likely be a while before we have a clear idea of what's happened in this conflict.