Another possibility: chosen one knew there was corruption in Ukraine but didn't have the slightest interest in supporting a robust anti-corruption policy. If he was perhaps he would have expressed an interest in some cases other than the ones involving the Bidens. Sometimes you have to listen for the dog that didn't bark.
It also bears noting that chosen one's cronies (err representatives) such as Perry, Giuliani, Parnas and Fruman seemed more interested in aligning themselves with the more corrupt and disreputable elements of Ukrainian society. We don't have to get into the details of what all his cronies did. His own actions are sufficiently damning. He removed an ambassador based on a smear campaign from corrupt people who were upset at her work against corruption. It seems very much the case that chosen was not only uninterested in rooting out corruption but indeed very much interested in aligning himself with the corrupt and seeing what he could get out of that.
Final point: I don't think this is the case but even if chosen one had a legitimate desire to root out corruption (and here some rolling of the eyes is appropriate), it is not legitimate to use that as cover to strongarm a vulnerable country into participating in a disinformation campaign aimed at the American voter. It bears noting that his real ask was for a public announcement of an investigation of the Bidens (in the words of Bill Taylor chosen one wanted Zelenskyy in a "public box"). That is different from an investigation itself. It is a distinction worth remembering. Serious investigations typically don't start with public naming of the targets by the president of a country.
We all know what went down and no amount of skillful lawyering (and so far I've only seen unskillful lawyering from chosen one's defenders) is going to obscure that.
