Russia's problems have existed for a long time now, much longer than the time of this war.
Years ago, Putin implemented a program to pay all women in Russia $5,000 for each baby they would birth. Simple reason being the population decline in Russia was so significant that they needed to do something to counter the loss of population.
Russia has been losing population in many ways for years. Babies/children were being adopted out of the country in large numbers. Caucasian babies were highly desired in the USA and European countries.
Next, women were leaving the country to the tune of 50,000+ per year to marry men in western nations. Most of these women were highly educated, looking for a desirable man to share a life with. Many left Russia with 1-2 children in tow to escape the country for a better life.
Last but not least, the Ukrainian war. Russia is waging a full scale war on what was a sister nation not that long ago. There really is no justifiable reason for this endless war being waged, and yet Russia/Putin is fully prepared to deplete the entire population of Russia to conquer a nation so that Putin can seize that nation's mineral wealth. That is the only reason I see for the decisions being made to date.
The number being indicated around 1 million having fled Russia to avoid the meat grinder in Ukraine I suspect is a very low number. I would imagine it is more in the neighborhood of 3-5 million fleeing for their lives.
All of the above will result in further declines in births in Russia, worsening an already bad situation.
And note this, Russia is largely NOT controlled by the brain trust, but by the masses, folks with little education. Fact is Russia values folks that are highly educated at an absolute minimal level. The faults of this type of society leave it in a very weakened state. Not competitive on the global stage. And with the war, Russia has become a pariah, the modern day Nazi Germany, perhaps worse.