
Hi @frob,
If you want to override the permission with a lower one, I'm afraid it is impossible in SharePoint Online. You can raise a new thread in the SharePoint feedback portal: https://feedbackportal.microsoft.com/feedback/forum/06735c62-321c-ec11-b6e7-0022481f8472. Microsoft will take it into if it is highly voted. Comment here if I have any misunderstanding.
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