Beyond the number of troops, tanks, missles, and military leadership, much of what now happens in Russia's invasion of Ukraine will depend on Vladimir Putin, President of Russia, related to "ideology and political culture on the one hand and political stability and regime legitimacy.", writes Alexander J. Motyl--professor of political science at Rutgers University-Newark and a specialist on Ukraine, Russia and the USSR, on nationalism, revolutions, empires and theory--in an excellent article on what factors are important beyond the military balance between Russia and Ukraine.
What it boils down to is that "...many of Putin’s recent public appearances range from incoherent to embarrassing: They contrast hugely with the self-assured, even arrogant, style of his earlier performances. Today’s Putin is a weak, bloated, and uncertain man who was shocked by Yevgeny Prigozhin’s attempted coup and didn’t know for days how to respond, perhaps because he understood that the run-up to the coup could not have escaped the attention of the secret police, which did nothing to nip it in the bud. Can such a Putin lead a vast country and conduct a war successfully? The question is at least open."