How do you split multiple columns at the same time, based on an index column?

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("hYzLDYAwDENXsXL2BcoC5U9BLFB1/zVwOfREixQrkf3iGK0zWi95wmvtxGGJ8fW+/Mw7aSQmYtYViFBeKpGrR7lwkBZiJTZdJ3ERt6bUNgH3BwxNID0=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Index = _t, IndexMax = _t, Column1 = _t, ColumnN = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Index", Int64.Type}, {"IndexMax", Int64.Type}}),
    #"Unpivoted Other Columns" = Table.UnpivotOtherColumns(#"Changed Type", {"Index", "IndexMax"}, "Attribute", "Value"),
    #"Replaced Value" = Table.ReplaceValue(#"Unpivoted Other Columns",each [Value],each if List.Count(Text.Split([Value],", "))=[IndexMax] then Text.Split([Value],", "){[Index]-1} else [Value] & " - Discrepancy",Replacer.ReplaceValue,{"Value"}),
    #"Pivoted Column" = Table.Pivot(#"Replaced Value", List.Distinct(#"Replaced Value"[Attribute]), "Attribute", "Value"),
    #"Sorted Rows" = Table.Sort(#"Pivoted Column",{{"IndexMax", Order.Ascending}, {"Index", Order.Ascending}})
in
    #"Sorted Rows"

How to use this code: Create a new Blank Query. Click on "Advanced Editor". Replace the code in the window with the code provided here. Click "Done". Once you examined the code, replace the Source step with your own source.