I conditionally replace the Binary file in the Content column to create a column of tables:

= Table.ReplaceValue(Source,each [Content],

each if Text.Contains([Extension],".xl") then Table.TransformColumns(Source, {"Content", each Excel.Workbook(_)})

else if [Extension] = ".txt" then Table.FromColumns({Lines.FromBinary([Content])})

else if [Extension] = ".csv" then Csv.Document([Content],[Delimiter=","])

else [Content],

Replacer.ReplaceValue,{"Content"})