filtering and saving into new column

You will need to remove complete Source line in my code and replace that with your source line. _t are generated when you use PQ's Enter Data feature to generate data rather than pulling from a source.

Use the below new code for your task

let
    Source = Excel.CurrentWorkbook(){[Name="Table5"]}[Content],
    BuffList1 = List.Buffer(Source[Column1]),
    BuffList2 = List.Buffer(List.RemoveNulls(List.ReplaceValue(Source[Column2],"",null,Replacer.ReplaceValue))),
    BuffList1Count = List.Count(BuffList1),
    GenList = List.Generate(()=>[x=Text.Combine(List.Select(BuffList2,(a)=>List.Contains(Text.Split(BuffList1{0}," "),a, Comparer.OrdinalIgnoreCase)),", "),i=0], each [i]<BuffList1Count, each [i=[i]+1, x=Text.Combine(List.Select(BuffList2,(a)=>List.Contains(Text.Split(BuffList1{i}," "),a, Comparer.OrdinalIgnoreCase)),", ")], each [x]),
    Result = Table.FromColumns(Table.ToColumns(Source)&{GenList},Table.ColumnNames(Source)&{"Result"})
in
    Result