Is it possible to clone a G Suite account from one domain to the same domain? I need to preserve a full copy at a given point of one account (including emails, Google Docs, calendar, etc.) that I can access in the future.
AFAIK G Suite doesn't include a built-in feature to "clone" G Suite accounts but you could use the export organization's data and transfer features to make a copy of several account files and data. For details see
Note: There is a service called Vault that:
... lets you retain, hold, search, and export data to support your organization’s archiving and eDiscovery needs
but it doesn't include all the account data.