Technically, you could use the "Update Profile" action in JO to put the
user into the segment you created by updating the fields that would
qualify the person into the segment. See update profile documentation
here -Jumping from one journey to another | Adobe Journey Orchestration.
The timing of this segment realization follows the standard segment
realization SLA's defined today and will play into your expectations for
The current way to get detail from profile is to use the datasource for
Experience Platform in your custom action to grab whatever is needed
from that profile. The context of the triggering event (segment
qualification) only has what you noted. The datasource for Experience
Platform will allow you to grab whatever it is you've marked from
profile for Journeys.