It's the choice of Ukrainian people.
Do you actually have any remotely realistic conception of the Ukrainian people's wants? Have you bothered to look at surveys produced even by such outfits as Gallup and Thomson Reuters?
Zelensky does not equal the Ukrainian people.
Russia is objectively better able to run things than Ukrainians are. This applies to practically all things (with some notable exceptions). But in the things that matter, Russia delivers better outcomes.
1) Ease of access to government services: (both Russia and Ukraine are at the forefront in terms of digitizing things, but Russia is further still). America is light years behind both.
2) Healthcare - massive amounts are invested in Russia. Smaller regional towns in Luhansk and Donetsk that were acquired in 2014 have state of the art German MRI and CT scanners, let alone Moscow and bigger Russian cities. Ukraine has no such money.
3) Education - there is no question that Russian universities are, again, light years ahead of Ukrainian ones.
4) Practically every sector of the economy has a much bigger and much more efficient Russian player vs the Ukrainian equivalent.
5) Crime - petty crime, and violent crime are both significantly lower in Russia.
Ukraine is great on gloss and other forms of PR, but Russia still has a much, much more capable government than Ukraine. This can deliver better results for the people coming into Russian jurisdiction.