https://www.epo.org/en/node/it-possible-file-notification

Is it possible to file a notification concerning an opt-out from the competence of the Unified Patent Court with the EPO?

No, notification of an opt-out from the exclusive competence of the Unified Patent Court can only be filed with the UPC Registry. It cannot be filed with the EPO. For further details, please see the FAQ on the UPC website.