A straightforward solution is to set the "Role" field in [sys_group_has_role] as the Display Value.

When setting values for reference fields or variables, the field displayed is the one where the Display Value is marked as True.

In the screenshots below, which are taken from my Personal Development Instance (PDI), all Display Values are set to False.

Therefore, in the following example, the SysID appears as the Display Value. (Please note that these screenshots show how the catalog is displayed in the platform interface, not on the portal. The appearance of the variable you configured may differ. However, rest assured, this variable is a List Collector referencing sys_group_has_role.)

Next, I set the Display Value of the "Role" field in sys_group_has_role to True.

As a result, the role names should now be displayed.

Please note that this change will affect the display value of all fields and variables referencing [sys_group_has_role].

best regard.