What problems does russia have?
Again, in order of priority:
1) Self imposed manpower constraints (predicated on Putin's political fears related to a new wave of mobilization)
2) Issues with command and control, morale, and training. Broadly similar to Ukraine's problems. Because we are much bigger, we can easier "absorb" these problems, however.
3) Restricted access to Western dual-use technologies.
4) A deteriorating economic outlook.
That's all I can think of.
Generally speaking - Ukraine and Russia have very similar problems - on surface level. If we have problems exporting oil/gas & metals, they have problems with grain and other agri produce. If we have problems importing Western tech, they have problems importing Chinese tech. We need to find ways to plug our budget deficits through new issuances of bonds or raiding Gazprom and friends' treasuries, and they need to find ways of plugging their budget holes through soliciting new tranches of Western financial aid.
The problem for Ukraine is that all these problems are much more exacerbated than they are in Russia; this is due to their smaller size, their total dependence on outside help, and an overall greater fragility in the economic and political spheres.
In Russia, we say - «Пока толстый сохнет, худой сдохнет». Translated, this means, "While a fat man withers, a thin man perishes".
Russia's accumulated fat and muscle mass means that it can last much, much longer than emaciated Ukraine.