textjoin

Thanks to all... now i try

Perhaps with 365000 rows Power Query, as OliverScheurich​  suggested,  will be better. However, formula

=GROUPBY (HSTACK(Tabelle1[Col1],Tabelle1[Col2],Tabelle1[Col3]),Tabelle1[Col4], ARRAYTOTEXT,0,0)

also works.

As for Power Query I'd add first colmns

let
    Source = Excel.CurrentWorkbook(){[Name="Tabelle1"]}[Content],
    names = Table.ColumnNames( Source ),
    DeclareType = Table.TransformColumnTypes( Source,
        List.Transform( names, each {_ ,type text} ) ), 
    CombineTesxt = Table.Group(DeclareType, List.RemoveLastN(names, 1),
         {{"Text", each Text.Combine( [Col4], ", "),
         type text}})
in
    CombineTesxt

Both variants are in attached file.

Does the screenshot show the intended result? This is done with Power Query and in the attached file you can add data to the blue dynamic table. Then you can click in any cell of the green table and right-click with the mouse and select refresh to update the green result table.

I've only made a small sample table however Power Query is the perfect tool for huge databases. It can actually handle transformation of several million rows.