You are just assuming that both sides lie. Ukraine has been shown to be lying. There is no evidence that the Russians are lying, only a disparity between their numbers and Ukraine's numbers. To say that Western observers support the Ukraine numbers is only to say that the West, who created the Ukraine corruption swamp, has a vested interest in sticking to the narrative that they are helping to create.
In any case, the Russian casualties at last note were ~5,000 (~1,500 dead), while their count for Ukrainians, whose bodies they are collecting and counting in the field, is more on the order of ~20,000 (~10,000 dead). Essentially all the Ukrainian armor and aircraft are destroyed. Their ammo dumps and fuel depots are destroyed, so they are out of fires and mobility. The West throws in weapons and the Russians collect them as trophies off the field, unfired, abandoned by fleeing Ukrainians, and being remanded to the Donetsk forces for their armament. The Russians have no problem using their UAVs, Su-25s, and attack helicopters (beyond the reach of any Ukraine aircraft operating from western Ukraine). Currently, Russia has encircled ~60,000 Ukrainian troops in a "cauldron" where they will be attritted by artillery or desertions---until they surrender or are finally destroyed.
You are just assuming that both sides lie. Ukraine has been shown to be lying. There is no evidence that the Russians are lying, only a disparity between their numbers and Ukraine's numbers. To say that Western observers support the Ukraine numbers is only to say that the West, who created the Ukraine corruption swamp, has a vested interest in sticking to the narrative that they are helping to create.
In any case, the Russian casualties at last note were ~5,000 (~1,500 dead), while their count for Ukrainians, whose bodies they are collecting and counting in the field, is more on the order of ~20,000 (~10,000 dead). Essentially all the Ukrainian armor and aircraft are destroyed. Their ammo dumps and fuel depots are destroyed, so they are out of fires and mobility. The West throws in weapons and the Russians collect them as trophies off the field, unfired, abandoned by fleeing Ukrainians, and being remanded to the Donetsk forces for their armament. The Russians have no problem using their UAVs, Su-25s, and attack helicopters (beyond the reach of any Ukraine aircraft operating from western Ukraine). Currently, Russia has encircled ~60,000 Ukrainian troops in a "cauldron" where they will be attritted by artillery or desertions---until they surrender or are finally destroyed.