What do you do about people who are leaving your organization and the documents they owned in Nextcloud?
For example, if one person in the organization was sharing documents with others and then they leave the organization, how do you make sure the documents/files they were sharing with others are still available to the person who they were shared to once you delete that user from your Nextcloud? Or do you not delete the person
I don’t think it’s a Nextcloud problem, but rather an organisational requirement. Strictly speaking, a file shared by a user is a user’s file and therefore not really relevant if the person goes to the company. Comparable to Microsoft OneDrive. The data is then simply deleted e.g. because of GDPR.
Files that are actually relevant should be stored in group folders or with Nextcloud 31 named team folders. This is comparable to Microsoft SharePoint.
However, neither the Nextcloud nor the Microsoft approach is actually comparable with management in a company hierarchy, e.g. by department, as used to be the case with network drives. You should therefore always clarify this for your company regardless of the resulting solution.