Top N + Others on visualization (having difficulties with RANKX)

Hi Experts,

I've been trying for a while now to implement a TOP N + Others (As in, show the share of sales for the top N brands but include a representation for the rest of the brands). I tried following this guide: Filtering the top products alongside the other products in Power BI  but haven't been successful.

This is my main table and there are no relevant relations here:

 The dashboard itself is always filtered by Category and Share Type and I want this Top N to be responsive to filtering on other visuals (ie: by manufacturer, by cluster player, etc)

The ranking measure I created following the guide isn't responsive and to be honest I don't think it's doing what I mean for ti to be doing.

Ranking Top X = 
IF (
    ISINSCOPE ( 'QuickFlash'[BRAND] ),
    VAR TotalValue =
        -- This is the same as the [MONTH Value] measure which I made explicit here.
        CALCULATE (
            SUM(QuickFlash[SHARE VALUE]),
            AND(
                MONTH(QuickFlash[MONTH]) = MONTH(MAX(DataMax[MONTH])),
                YEAR(QuickFlash[MONTH]) = YEAR(MAX(DataMax[MONTH]))
            )
        )
    RETURN
        IF (
            TotalValue > 0,
            VAR VisibleBrands =
                CALCULATETABLE (
                    VALUES ( 'QuickFlash' ),
                    ALLSELECTED ( 'QuickFlash'[BRAND] )
                )
            VAR Ranking =
                RANKX (
                    VisibleBrands,
                    [MONTH Value],
                    Total Value
                )
            RETURN
               Ranking
        )
)

I didn't limit the number of ranking brands in this measure because I'm still trying to figure out what I'm doing wrong.

Anyway, at the moment, if I look at the brands and the ranking measure in a matrix I get:

- Some brands with repeat ranking values, even though they don't tie for value (Brand A, B and C are ranked as first, but Brand A has a Month Value of 172k while B has 188k and C has 45k;

- Some numbers that just don't make sense, as if it's not really aggregating by brand (ie: Brand D is ranked 1045 even though there are less than 200 brands total (less than 100 with the filters being used)

Sample data can be found here in excel format: Sample Data