Peeling off Russian forces is exactly what Ukraine has already done with this force. I believe it was entirely the point.
Russia is forced not to ignore this for numerous reasons, and it forces them to attack to expel the Ukrainian forces. Successfully attacking with conscripts is a more difficult proposition than defending.
Ukrainian forces inside Russia can continue to force the confrontation by advancing into undefended territory and/or launching limited small scale attacks to be a constant wound inside of Russia. Ukrainians have already been conducting these attacks on reinforcements on their way to stop the main Ukrainian forces.
All the while Ukrainians inside Russia can refuse to assault defended positions. Which is exactly what they did initially. They bypassed the heavy positions and refused to engage in heavy force on force assaults. Instead as local defenders they are creating a lopsided local situation.
As an aside, where are Russian air assets? Inside Ukraine the skies were contested, but the apparent inability of air assets to repel Ukrainians from Russian territory with air power is not a good sign for Russia.
I assumed naturally they did bring AA, but the fact that AA of a force on the move is able to apparently overcome the ability of Russia to deploy air power in any significant way on its home turf is really something.