Dynamically query all SharePoint sites with same list name, but can't refresh online

I have a similar issue, 

A list of sharepoint sites stored in a list.  I just wat to know how many files have been submitted to each site each month

Works fine on pbix, but too dynamic for dataflow or service refresh.  

This should be possible, its within Microsoft's infrastructure and surely not that unusual

Custom function to count all files by month

let
    Source = (SP as text ) =>

let
    Source = SharePoint.Files(SP),
   
    #"Filtered Rows" = Table.SelectRows(Source, each Text.Contains([Folder Path], "/Sharing/")),
    #"Changed Type" = Table.TransformColumnTypes(#"Filtered Rows",{{"Date created", type date}}),
    #"Grouped Rows" = Table.Group(#"Changed Type", {"Date created"}, {{"Files by Day", each Table.RowCount(_), Int64.Type}})
in
    #"Grouped Rows"
in
    Source