This is not quite what happened. Illia Kyva [1] is a Ukranian politician who was a former presidential candidate, as well as the head of Socialist Party in Ukraine. He is pro Russia and skeptical of Western interests and motivations in Ukraine. After the war this did not change and he supported Russia while blaming Zelensky and urging him to resign.

Zelensky then decided to purge him and his entire party, charging him with treason. This led to Kyva making increasingly unhinged claims and recommendations. Among those were that Russia should nuke Ukraine, and that Zelensky had secretly fled to Poland. Some Russian outlets (I cannot find this story on RT, but perhaps I missed something?) ran this story such as here [2].

The article certainly doesn't state it as a fact. Instead it recounts the events in a relatively impartial way - two Ukrainian lawmakers said he fled. Rumors of something similar were spread shortly before the article was published and Zelensky rejected them while providing video evidence of himself in Ukraine. It also mentions that the US reportedly offered to help him escape Ukraine, and also that he rejected the offer. End of article.

[1] - https://en.wikipedia.org/wiki/Illia_Kyva

[2] - https://sputniknews.com/20220304/zelensky-left-ukraine-for-p...