They're not necessarily as high. I ran across an interesting
twitter thread from a retired US general earlier today about the issue of Russian losses and his opinion on the subject. The short of it being that in his judgment, most of the vehicles that Russia's using are death traps if they get hit. While Ukraine's using a lot of the same shit, they're the ones using infantry with anti-tank rockets to blow up vehicles which will usually contain multiple people that'll be injured or killed. He also thinks Ukraine's better able to treat and evacuate its wounded than Russia is. If his opinion is accurate, it would certainly explain quite a bit about why estimates of Russia's military losses have ranged so much higher than estimates of Ukraine's military losses.
So it's quite possible for Ukraine's military losses to be much lower than Russia's simply as a matter of how they're fighting. Ukraine can lose one or two guys per vehicle destroyed by infantry weapons, and still come out ahead.