Depends how you count “big”. Russia-Ukraine has had about 1 million deaths, and has completely changed how Europe thinks about security- it’s hardly a sideshow. Then again, not much territory has changed hands and there has been no regime change yet.
Not true, prior to 2022 February Russia controlled small parts of Donetsk and Luhansk oblasts, now they control them almost entirely, as well as good chunks of Zaporizhzhia and Kherson oblasts.
All were captured during their thrift store blitzkrieg. Kherson, Zaporizhzhia and Mariupol were captured because pro Russian rats sabotaged mine defenses in Kherson oblast.
The casualty-to-death ratio in Ukraine is surprising for modern times, especially on the Russian side. Counting civilians, Ukrainians, Russians, I can see the death count being close to 1M. Partisan sources already put Russian combat losses at around 1.2M personnel. Ukrainian losses might be more than half what Russian losses are. The 1M deaths estimate doesn't seem outlandish.