I was going to reply to all the points you made but I read your source and it is excellent, I will use it in the future. https://en.zona.media/article/2022/05/20/casualties_eng

So you make fun of Joe Blog even though he uses Russian (where available) data and other sources. But let's use your "reliable" source "which shows Russian casualties of 43,000". If you had bothered to read more than just the head line you would have seen.

"approximately 47,000 Russians under the age of 50 had died in the Ukraine war. However, these figures represent only a partial account and do not reflect the full extent of the casualties."

"The actual death toll is likely significantly higher."

"This week, CIA Director William Burns penned a column in Foreign Affairs estimating the total losses of the Russian army—killed and wounded—at 315,000. At first glance, this figure might seem significantly different from our own count, but in reality, it’s not, and we regard Burns’ estimate as close to the truth."

"43,000 obituaries found on social networks suggest approximately 80–90,000 actual deaths."

And the 300k estimate is assuming a 3 to 1 wounded to killed ratio. 90,000 killed and (3 times) 270,000 wounded is from Feb 2nd. On that day Ukrainians were claiming ~387,060 casualties, pretty close to the 360,000 from your reliable source.