I recently tried to get Unified Auditing going for Oracle Database XE. I could not really find instructions – not even through ChatGPT – and finally reached out to Gerald Venzl, the community champion at Oracle who is one for the key people behind Oracle Database XE. I learned from him that Unified Auditing is not supported with XE. Enabling Unified Auditing requires relinking the Oracle Database binary (Oracle Database documentation on unified auditing) which is not allowed/provided for XE.
If you – like me – want to have unified auditing on Oracle Database XE, look no further. It cannot be done. Sad face.