Whether to retain consultation/interview records when cleaning up former employee accounts

I have a question while organizing records of former employees.

Usually, email accounts and internal system permissions are organized based on the date of resignation, but I was confused about how to manage interview records and grievance memos held by the HR team.

I think simply keeping the details of the resignation interview together in the departing employee file would suffice, but I am wondering if I should further restrict access permissions if counseling or grievance-related content is mixed in.

I might need to check it later even after I leave the company, but leaving it accessible for too long is also a burden.

How do other companies organize interview records or grievance counseling data regarding departing employees?

Do you keep the files for departing employees together with their HR files, or do you manage them in separate folders?