Performance problem with simple measure chain

Hi amitchandak 

The model hasn't got any unusual relationships.

Unfortunately I can't share the model as it contains company data ☹️

The only other useful information I could provide is this:

and the query performance code (which I don't fully understand yet)

// DAX Query
DEFINE
  VAR __DS0FilterTable = 
    TREATAS({"6 weeks"}, 'WeekRange'[Week Range (for AWS)])

  VAR __DS0FilterTable2 = 
    FILTER(
      KEEPFILTERS(VALUES('dimCalendar'[DATE: DATE])),
      AND(
        'dimCalendar'[DATE: DATE] >= DATE(2020, 1, 1),
        'dimCalendar'[DATE: DATE] < DATE(2020, 12, 1)
      )
    )

  VAR __DS0Core = 
    SUMMARIZECOLUMNS(
      ROLLUPADDISSUBTOTAL('dimProduct'[PRODUCT: NUMBER TEXT], "IsGrandTotalRowTotal"),
      __DS0FilterTable,
      __DS0FilterTable2,
      "Number_of_Weeks_for_AWS__Default__26_", 'M E A S U R E S'[Number of Weeks for AWS (Default: 26)],
      "Product_Age_in_Weeks__new_", 'M E A S U R E S'[Product Age in Weeks (new)],
      "Total_Quantity_Shipped", 'M E A S U R E S'[Total Quantity Shipped],
      "Quantity_Sold__over_nWeeks_", 'M E A S U R E S'[Quantity Sold (over nWeeks)]
    )

  VAR __DS0PrimaryWindowed = 
    TOPN(502, __DS0Core, [IsGrandTotalRowTotal], 0, 'dimProduct'[PRODUCT: NUMBER TEXT], 1)

EVALUATE
  __DS0PrimaryWindowed

ORDER BY
  [IsGrandTotalRowTotal] DESC, 'dimProduct'[PRODUCT: NUMBER TEXT]

Thanks