Appending query to itself, keeping previous rows

Imagine the weekly update is like in the blue table (screenshot below) and the combined one from earlier updates is the green one and comes from an earlier run of the query

The following M-code will connect to tblSource (Source)  AND tblPQ (History) and then append Source to History to create an extended tblPQ.

let
    Source = Excel.CurrentWorkbook(){[Name="tblSource"]}[Content],
    History = Excel.CurrentWorkbook(){[Name="tblPQ"]}[Content],
    #"Appended Query" = Table.Combine({History, Source}),
    #"Changed Type" = Table.TransformColumnTypes(#"Appended Query",{{"Snap", type date}, {"ID", type text}})
in
    #"Changed Type"

It results in this:

and a next run may look like this:

 etc.