This field should be able to get enabled as a column, and it should automatically populate with the people who are assigned to any subtasks under a given task

Example Tasks

Task 1 -> Assigned to PersonA

Subtask 1.A -> Assigned to PersonA

Subtask 1.B -> Assigned to PersonB

Sub-Subtask 1.B.1 -> Assigned to PersonD

Subtask 1.C -> Assigned to PersonC

Task 2 -> Unassigned

Subtask 2.A -> Assigned to PersonA

Subtask 2.B -> Assigned to PersonC and PersonE

When we create a column to display this new field type, the list view should look something like this. Let's say the new Field column is called Worker(s)

Example List View

Task Name | Assignee | Worker(s)

Task 1 PersonA PersonA, PersonB, PersonC, PersonD

Subtask 1.A PersonA -

Subtask 1.B PersonB PersonD

Sub Subtask 1.B.1 PersonD -

Subtask 1.C PersonC -

Task 2 Unassigned PersonA, PersonC, PersonE

Subtask 2.A PersonA -

Subtask 2.B PersonC, PersonE -

Worker(s) is populated by the Assignees of the Subtasks

This cannot be done with Automation at the moment, but a Custom Field with automation can also work similarly.