How to pivot with multiple values column?

If you do decide to restructure your data, here's one way to do it in the query editor.  To see how it works, just create a blank query, open the Advanced Editor and replace the text there with the M code below.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("TYyxDQAgCAR3obZQXgfQNYj7ryE+hlhcwT05M2m1SpHpNEfJLiaa/jo4gx7p8bZOH53FOzZ8nfVczz7SK9v83wc=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [PROID = _t, Store = _t, M1 = _t, M2 = _t, M3 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"PROID", Int64.Type}, {"Store", type text}, {"M1", Int64.Type}, {"M2", Int64.Type}, {"M3", Int64.Type}}),
    #"Added Custom" = Table.AddColumn(#"Changed Type", "Custom", each Record.RenameFields(Record.RemoveFields(_, {"PROID", "Store"}), {{"M1", [Store] & " M1"}, {"M2", [Store] & " M2"}, {"M3", [Store] & " M3"}})),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"M1", "M2", "M3"}),
    #"Pivoted Column" = Table.Pivot(#"Removed Columns", List.Distinct(#"Removed Columns"[Store]), "Store", "Custom"),
    #"Expanded A" = Table.ExpandRecordColumn(#"Pivoted Column", "A", {"A M1", "A M2", "A M3"}, {"A M1", "A M2", "A M3"}),
    #"Expanded B" = Table.ExpandRecordColumn(#"Expanded A", "B", {"B M1", "B M2", "B M3"}, {"B M1", "B M2", "B M3"})
in
    #"Expanded B"

Pat