Dax Query Month Year filter issue in Report Builder

[PeteDTG]

Hello,

I have a report I have built in Power BI and I am copying over the Dax Query into Report Builder, which is being used as a filter for month year. I have changed the month year column to a date format in Power BI, as shown in the image below. 

However, when copying over the Dax Query it changes the MonthYear column to datetime. Here is the Dax Query:

  // DAX Query
DEFINE
  VAR __DS0FilterTable = 
    TREATAS({"FALSETRUE",
      "TRUEFALSE"}, 'edw amcs_prod_factTonnage'[Exclude/Include])

  VAR __DS0FilterTable2 = 
    TREATAS(
      {DATE(2021, 8, 1),
        DATE(2021, 9, 1),
        DATE(2021, 10, 1),
        DATE(2021, 11, 1),
        DATE(2021, 12, 1)},
     'edw dimDate'[MonthYear]
    )

  VAR __DS0FilterTable3 = 
    TREATAS({"2021"}, 'edw dimDate'[Year])

  VAR __DS0Core = 
    CALCULATETABLE(
      SUMMARIZE('edw dimDate', 'edw dimDate'[MonthYear], 'edw dimDate'[Month]),
      KEEPFILTERS(__DS0FilterTable),
      KEEPFILTERS(__DS0FilterTable2),
      KEEPFILTERS(__DS0FilterTable3)
    )

  VAR __DS0PrimaryWindowed = 
    TOPN(501, __DS0Core, 'edw dimDate'[Month], 1, 'edw dimDate'[MonthYear], 1)

EVALUATE
  __DS0PrimaryWindowed

ORDER BY
  'edw dimDate'[Month], 'edw dimDate'[MonthYear]

This is causing my Report Builder filter to show month year as a datetime, as shown below. It works fine, but looks weird. How to I go about fixing this, so it actually shows month year (September 2020)?

Can I do this in the Dax Query or does it have to happen in Report Builder? Haven't had much success with either yet.

Thank you!!