M365 DLP - supported file types and using file properties as a condition

Hi All,

I am looking to help implement M365 DLP for email that can interrogate the properties of files to look for a specific metadata tag/property that has been applied by a 3rd party system.

1. Is there an M365 learn page that lists the supported file types by M365 DLP? The only one I could find was this one - http://Use mail flow rules to inspect message attachments in Exchange Online | Microsoft Learn 
2. For the supported file types shown on the linked article, can I use the "Document Property" condition in an M365 DLP rule to identify an attribute and presence of a value? (Similar to identifying an MSIP tag)
3. For file types that fall outside those listed on the linked article, is there a way to interrogate the properties of these files using a DLP policy?

Thanks

David