Move Mail from personal Mailbox to public folder (EWS/Graph)

Question

I am trying to move a mail item from a personal mailbox to a public folder.

As I understand, this is still not possible using Microsoft Graph because public folder access is not supported.

Using Microsoft 365 Groups instead of public folders to store mail items is no option, as I would need to organize them in sub folders. Those are not supported by the Windows Outlook client.
Furthermore I am not clear about how to move a mail to a group using Graph API.

Therefore, my current work concentrated on EWS.
Trying to move a mail item using Move or Copy results in the following error:
'Access to this API requires the following permissions: 'MailExport-Internal.Read.All,MailExport-Internal.Read.Shared,MailExport-Internal.ReadWrite.All,MailExport-Internal.ReadWrite.Shared'. However, the application only has the following permissions granted: 'full_access_as_app,Mail.ReadWrite,Mail.Read,Mail.Send'.";error_category="invalid_grant"

Those permissions seem to be internal - I am unable to grant them.