Trump ran a mafia style extortion scheme against Ukraine. He had an offer they couldn't refuse.
What happened then is they hid the documentation in an ultra-secure server, and tried to spike the whistleblower report, among other things. That's a coverup.
When the whistleblower report leaked, they went into damage control mode. That was the next phase of the coverup.
Trump made the mistake of releasing part of the phone call, with the now famous line, "I have a favor to ask, though". That revealed a number of abuses of power, and set off the third phase of the coverup.
They tried to block people from going to Congress to testify, and blocked the release of nearly all documents.
They then started in on the 4th phase, tie Congress up in the courts so they could run out the clock.
So I was wrong. That's a coverup of a coverup of a coverup of a coverup. It's also implicitly a series of admissions of guilt.
Nixon tried to block witnesses and withold documents. But he was a piker compared to Trump.