There's circumstantial evidence.
Zelensky was a comedian of average wealth before becoming PM. Now he's worth over a billion dollars, with homes in Florida, London, and Tel Aviv.
Similar to the circumstantial evidence of 2020 election fraud. Six states in which Trump was leading stopped the count. When they resumed, Trump lost every state.
In both cases, there's no smoking gun. But the circumstances strongly imply something fishy.
“Now he’s worth over a billion dollars, with homes in Florida, London, and Tel Aviv.”
Source ?
"Fact check: No proof to back claims on Ukrainian President Volodymyr Zelenskyy's assets and income". USA today. April 5, 2023, (link).
President Zelensky Is Not A Billionaire. So How Much Is He Worth? Forbes. April 20. (link).
Social Media Posts Make Unsupported Claims About Zelensky’s Income, Net Worth. Factcheck.org. July 21, 2022. (link).
The "circumstantial evidence" to support Hersh's unsupported claims, are based on unsupported claims. Zelensky ran a successful film and TV production company. What Russian propagandists did, was take the what was know about his business, then twisted it into a narrative of personal corruption and applied it to his Presidency. When Russia has a bad day on the battlefield, in a few days they will claim they inflicted two to three times as many casualties in a single engagement. Another trick is to take a old story and previously reported numbers, and rewrite it to fit the a current need to counter a story by one-upping the Ukrainian side, basically a pissing contest of who can tell the bigger story. Once you see the patterns of how propagandist work, it is easier to filter it out.
One of the basic rules is, no matter how bad the US and western news is, Russian state news is always worse.