The only thing that I know 100% is true is that Russia lies. This is not to say that other governments don't all lie, because they do. However Russia is on a totally different plane of lying. To paraphrase Mrs. Irish "Russia would lie if the truth was a better story." The only time the Russians don't lie is when a partial truth or half truth fits their narrative. For instance... The whole Ukrainian Nazi thing. Are there Nazi's in the Ukrainian government and armed forces? Sure there are. But I don't believe there are any more than there are Fascists in certain other governments and militaries.
Just like now, the Russians are saying that this whole time the "real" strategy was to confuse the Ukrainians, by faking an attack on Kiev when all they really wanted was to secure the Eastern areas of Ukraine. Well... That's total bullcrap, they wanted Kiev like a baby wants milk, but they got their asses kicked and are being forced to pull out. Then there's the lie that they didn't execute civilians. They even went so far as to say that they delivered over 400 tons of "humanitarian aid" to those places. If they had that much supply capability, then why were their own troops looting stores and civilians to get some food to eat? When someone goes further than simply denying something and makes up and even greater lie, then you know they are lying. For instance, you ask one of your kids, "Did you eat all the ice cream?" and they answer, "I haven't touched the ice cream." You know they are lying, because instead of just saying "no." they add the "I didn't touch it." part.
The only way to understand Russia is to simply understand that every word that comes out of their mouth is a lie and act accordingly.
Now... how much of what is coming out of the Ukrainians is a lie, I don't know. They were ingrained in that Soviet institution of systematic lying, but I think that their back is against the wall so bad that they have to be telling the truth more often than not. The reason being, if they are caught fabricating stuff then the support from the rest of the world would quickly dry up, and without international support, they are dead.
It reminds me of a stanza from the Doc Watson version of "The House of the Rising Sun" that goes like this...
Never believe what a bad woman tells you Though her eyes be blue or brown Unless she's standing on that old scaffold high Sayin' boys they won't let me come down...
Well boys, Ukraine is standing on that old scaffold high right now facing the executioner, fighting for their right to exist, so based on my experience, they don't have a whole lot of choice but to tell the truth, at least about most of the important stuff.