Once Zelensky sends every Ukraine male, young or old, to their deaths,
Russia males will breed out Ukraine with 1/2 Russian Father, 1/2 Ukraine Female.
The problem with your scenario?
Rocco “Condoms” comment doesn’t recognize abortion is a very typical and frequently used birth control method in Russia.
Also, intelligent Russia males have escaped across national border or if left behind just are too drunk to be able to perform. If perchance a Ukrainian mother did conceive the next generation will be raised by Ukrainian moms!