Side note: This data is generally reliable given that Ukraine is not a very authoritarian country, so people would not feel an incentive to lie on these surveys.
It's also reliable because Zelenskyy has poor approval ratings pre-war, proving that nobody was afraid to say they disapproved of him or anything.
Ukraine twice voted an incumbent president out of office since its independence, in 2005 and 2019. And Yanukovich was impeached in 2014. In the same period of time, the US also voted out two presidents. Of course people who claim Ukraine is some authoritarian state don't like to hear that. Yet a Russian president remains to be defeated in a regular election.
However, it would be funny if Zelenskyy wins another term by a bigger margin and a higher vote share than Putin is "reelected" by.