Does the loss include only the dead or does it include wounded and captured?
A better question would be whether the Ukrainian casualties lists include their dead left in Russian hands.
A fairly consistent claim by the Russians is that the Ukrainians don’t want to claim their dead even when the Russians offer them ceasefires and safe passage to collect them.
I noted that the Ukrainian casualties lists are also conspicuous in its omission of MIA.
Ever since the first widespread use of cannon and artillery, some of the battlefield dead are so throughly obliterated not enough is left to positively identify them or even not leave enough for their comrades to know a life was lost there.
This has been increasingly the case as weapons technology advance and become a lot more devastating.
This is why most historic military combat casualty lists combine KIA and MIA figures to give total deaths in combat.
Given the above Ukrainian propensity to not claim their dead, as well as the fact Ukraine is fighting a loosing war and constantly loosing territory, in addition to this war being largely an artillery fight, I think it’s entirely possible, likely even, that Ukrainian combat death numbers are vastly underrepresenting their losses even without considering deliberate government manipulation of the figures.