A Salesforce user has a unique username, a license, a profile, and optional roles and permission assignments. The license defines available capabilities; permissions operate within those entitlements. A record owner can remain part of historical data after leaving the company, so deactivation is different from deleting history.
Freeze blocks login while you handle dependencies. Deactivation removes the user's ability to sign in and can release an eligible license, but you still need a handoff plan for owned work, scheduled jobs, and other references. Don't solve a login issue by granting broad data permissions. First identify whether the problem is identity, license eligibility, session policy, or data access. This local simulator checks user definitions; hosted licensing and authentication remain scenario decisions.