[ Opinion ] Why Russia are failing in Lyman & Oskil fronts? Where are the troops / reinforcements?

It had been a disastrous September for the Russian side as Russia went from defeat to defeat; massive routs from the Balakliya Front, and then giving up the entire of Izyum front. Now Lyman is operationally encircled, and the Ukrainian forces are on the verge of a breakout over at the Oskil Front.