Performance journals, particularly HCMPerfJournal and HCMPerfJournalComment, are not available to be leveraged in any capacity and should be available for Dataverse reporting.

These are validated as missing per: https://docs.microsoft.com/en-us/dynamics365/human-resources/hr-developer-entities

Performance journals can currently be exported using a data entity but the notes are not part of any data entity. These notes are used to track both the employee’s progress towards their goals and would also be used to track that managers are reporting back in a timely manner on their subordinates.
Without the ability to get the notes on the data entity, we don’t really see of any way to report on this. It is essentially impossible to create HR reports using. DMF entity, dataverse, or Power BI.
If these were a part of any data entity we could find a way to combine them but as it stands there seems to be a large amount of crucial data that’s essentially unusable for reporting purposes.