Instead of thinking you may have read, try to find some evidence to back up your claims. I think you're probably not too wrong in this instance!
https://en.m.wikipedia.org/wiki/Casualties_of_the_Russo-Ukrainian_War links some of the various estimates for fatalities and casualties.
The fatality and casualties rates are high on both sides. Discounting the Ukrainian and Russian estimates which are ludicrously low for themselves and high for their enemy, Russian forces are being "reduced" at a rate of between 2-2.5 to 1.
If both sides were of equal size then this would be an absolute win for Ukraine. However given the relative size of the two forces and the longheld Russian tactic of grinding through their own forces then the Ukrainian side will be the one that runs out of able bodies first.