Show Only Top N In Column Level

Hi shareezsaleem You could use DAX to calculate total for each column and then rank them and apply filter in Matrix ..... Please try this out
Calculate Total for Each Column:

TotalValuePerColumn = SUM('Table'[Value])

Replace value with your numerical column
Rank Columns:

RankColumns = RANKX(ALL('Table'[WBS]), [TotalValuePerColumn], , DESC)

Filter Top 50 Columns:
Apply a filter in the matrix visualization to show only columns where RankColumns ≤ 50

You may not be able to achieve what you want in PBI, but here is something that is a workaround.

You need to unpivot your columns :

• Go to Transform Data

• Select your table 

• Select all WBS1 to WBS723 columns

• Right-click > Unpivot Columns

• Rename:

  • Attribute → WBS

  • Value remains as is

From :

To :

Then create 2 measures :

Total Value by WBS = 
CALCULATE(
    SUM('RawData'[Value]),
    ALLEXCEPT('RawData', 'RawData'[WBS])
)

WBS Rank = 
RANKX(
    ALL('RawData'[WBS]),
    [Total Value by WBS],
    ,
    DESC,
    Dense
)

Show Top WBS = 
IF([WBS Rank] <= 50, 1, 0)

The last measure you will use it as a filter on the visual.

See the real data

I want to reduce the column to top 5 based on the rank of WBS (which is the sum of values)

WBS Rank Matrix: