@Tom Meeus , Based on my research, the following licenses give you access to Microsoft 365 Defender feature via the Microsoft 365 Defender portal. In these licenses, I notice EMS E5 is included.
https://learn.microsoft.com/en-us/microsoft-365/security/defender/prerequisites?view=o365-worldwide#licensing-requirements
For Microsoft Defender ATP, I am not familiar. You can ask in the following forum to get more help.
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_defender?sort=LastReplyDate&dir=Desc&tab=All&status=all&mod=&modAge=&advFil=&postedAfter=&postedBefore=&threadType=all&isFilterExpanded=false&page=1
Thanks for your understanding and have a nice day!
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