You make some good points. I agree, any census done after Russia took Ukraine in 2014 can't be used and I don't doubt people who once considered themselves Russian started to consider themselves Ukrainian after Russia attacked Ukraine, but this was before all that so I don't think that's a problem.
And I'm not saying considering yourself Russian means you have allegiance to Russia, but I think there is a strong correlation between the two. Even if there's less of a correlation than I think, the percentage which considers themselves Russian is over twice that of the percentage which considers themselves Ukrainian. Maybe the Tatars align more with Ukraine than Russia, improving the balance, but idk.
And I'm not saying considering yourself Russian means you have allegiance to Russia, but I think there is a strong correlation between the two. Even if there's less of a correlation than I think, the percentage which considers themselves Russian is over twice that of the percentage which considers themselves Ukrainian. Maybe the Tatars align more with Ukraine than Russia, improving the balance, but idk.