Reviews

I recommend looking at tools that your organization uses already and adding the centralized share solution use case as a requirement to one of them.  If your organization uses M365, then SharePoint may work or OneDrive.  If your organization uses Google suite, look in that portfolio for a solution. Such approach will bring additional benefits of reusing all other capabilities that are probably expected such as e-discovery, mobile access, access administration, license entitlement reviews etc. etc.

Every industry sector (and public sector) has different requirements for retention. Understand your organization's required period of retention, work closely with your legal department to come up with a data classification policy and SOP first. Based on that you can come up with a retention policy. Unfortunately it is not a simple process. Please ensure you get executive sponsorship for this as a first step since it would be a cross collaboration across departments.