> On April 2, 2020, the administrator of the OGUsers forum publicly announced that OGUsers website was successfully hacked. Shortly after the announcement, a rival criminal hacking forum publicly released a link to download the OGUsers forum database, claiming it contained all of the forum’s user information. The publicly released database has been available on various websites since approximately April 2020. On or about April 9, 2020, the FBI obtained a copy of this database.
What about this implies parallel construction to you? The OGUsers databases (well, actually a couple, they've been hacked multiple times) has been publicly available for a while. Also, the discord chats and Vice article include details on selling accounts with desirable names - even if not explicitly linked to OGUsers (I don't recall off the top of my head if it was called out), you could track hacked accounts, see they were sold or discussed on OGUsers, and then give a look at the DB. That seems an obvious route of investigation to me?
Seems very convenient. Parallel construction?