I have a list of orders/containers, then run through multiple operations which also have multiple workstations which have multiple duplicate results

i would like to see

[order], [operation] ,[DISTINCT workstation]

SELECT 
  container.containername, 
  Operation.OperationName, 
  STRING_AGG(
    CONVERT(
      NVARCHAR(max), 
      ExecuteTaskHistory.ResourceName
    ), 
    ','
  ) as workstation 
FROM 
  Operation 
  RIGHT OUTER JOIN HistoryMainline ON Operation.OperationId = HistoryMainline.OperationId outer apply (
    select 
      distinct w.resourcename 
    from 
      ExecuteTaskHistory e 
      inner join HistoryMainline hml on e.HistoryMainlineId = hml.HistoryMainlineId 
      inner JOIN ResourceDef AS w on w.ResourceId = e.WorkstationId 
    where 
      HistoryMainline.ContainerId = hml.ContainerId 
      and HistoryMainline.OperationId = hml.OperationId
  ) ExecuteTaskHistory 
  LEFT OUTER JOIN Container ON HistoryMainline.ContainerId = Container.ContainerId 
Group By 
  container.containername, 
  Operation.OperationName

Have tried doing select top 1 but that will not provide correct results.