Here's the Mediazona again. They also mix casualty with death, but they clarify they are talking about the KIA. 19000 as of April 7 - those they could confirm. They state the actual number is higher.
https://en.zona.media/article/2022/05/11/casualties_eng

The pic here >>50078 says 16K-17.5K dating March 1, Mediazona counts 18K - again the confirmed, the actual number is higher. I highly doubt the US intel on this is worse than what this website gathers.