Russia's limited troop movement suggests they are running short

 ISW:

Russian forces continue to conduct meaningless offensive operations around Donetsk City and Bakhmut instead of focusing on defending against Ukrainian counteroffensives that continue to advance. Russian troops continue to attack Bakhmut and various villages near Donetsk City of emotional significance to pro-war residents of the Donetsk People’s Republic (DNR) but little other importance. The Russians are apparently directing some of the very limited reserves available in Ukraine to these efforts rather than to the vulnerable Russian defensive lines hastily thrown up along the Oskil River in eastern Kharkiv Oblast. The Russians cannot hope to make gains around Bakhmut or Donetsk City on a large enough scale to derail Ukrainian counteroffensives and appear to be continuing an almost robotic effort to gain ground in Donetsk Oblast that seems increasingly divorced from the overall realities of the theater.

Russian failures to rush large-scale reinforcements to eastern Kharkiv and to Luhansk Oblasts leave most of Russian-occupied northeastern Ukraine highly vulnerable to continuing Ukrainian counter-offensives. The Russians may have decided not to defend this area, despite Russian President Vladimir Putin’s repeated declarations that the purpose of the “special military operation” is to “liberate” Donetsk and Luhansk oblasts. Prioritizing the defense of Russian gains in southern Ukraine over holding northeastern Ukraine makes strategic sense since Kherson and Zaporizhia Oblasts are critical terrain for both Russia and Ukraine whereas the sparsely-populated agricultural areas in the northeast are much less so. But the continued Russian offensive operations around Bakhmut and Donetsk City, which are using some of Russia’s very limited effective combat power at the expense of defending against Ukrainian counteroffensives, might indicate that Russian theater decision-making remains questionable.

Ukrainian forces appear to be expanding positions east of the Oskil River and north of the Siverskyi Donets River that could allow them to envelop Russian troops holding around Lyman. Further Ukrainian advances east along the north bank of the Siverskyi Donets River could make Russian positions around Lyman untenable and open the approaches to Lysychansk and ultimately Severodonetsk. The Russian defenders in Lyman still appear to consist in large part of BARS (Russian Combat Army Reserve) reservists and the remnants of units badly damaged in the Kharkiv Oblast counteroffensive, and the Russians do not appear to be directing reinforcements from elsewhere in the theater to these areas.
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From the start of Russia's Special operation, their troop movements have appeared out of sync with reality and they seem to be getting worse after incurring significant casualties and losing combat power. This also could be attributed to a loss of leadership within the army and poor leadership by Putin and those around him.  When you have limited resources and use them unwisely it is usually a question of leadership.