This doesn’t have to be opinion.
Examine pre war info on population and size of inactive reserves. You don’t have to hear any numbers from either the Russia or Ukraine MoDs. Use the prewar data.
You can deduce all this yourself. For God’s sake believe nothing in the media. They have zero incentive to tell you the truth.
Population of ukraine is about half of what it was just prior to the war. Anybody who could get out got out...