Resource Alert for Emergency Contact DFF

Summary:

Unable to see/use the custom DFF in Resource Alert Creation

Content (please ensure you mask any confidential information):

I am doing a POC work for a client and we wanted to try if creating a DFF in the PER_CONTACT_RELSHIPS_DFF will work via resource alert creation in Alert Composer.
I have successfully created the DFF

But when I tried this out in Alert Composer, the user attribute is not showing and and when I manually enter the expression, always encounter an issue.

Version (include the version you are using, if applicable):

26A

Code Snippet (add any code snippets that support your topic, if applicable):