How to combine the date field for documents and attachments?

Although it is also a problem, it is not my main problem.

When I’m looking for a term, that I do not remember if it is in a document in my Windows folders or in an Outlook attachment, I use the ‘all’ view.
(I’ve tried a custom view of documents and attachments only, the problem is still there)

There is no way to sort documents and attachments together by ‘date’, since they are not using the same date fields.
•‘Date Created’ and ‘Date modified’ work for documents only
•‘Date/Time’ works only for Email attachments

Thanks

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