Table Expansion Optimization in Power Query

Hi lbendlin , here is my device specs:

I am using Table.Buffer and List.Buffer, but it's downloading a billion row in a 1 row increment. I am using the following code now:

let
    Source = ...,
    GSDATA = ...,
    ....= ...,
    #"Removed Other Columns" = Table.SelectColumns(ECHEM_DTL,{"SERIAL_NUM", "TEST_DATE", "TEST_TIME", "CFG_FILE", "DATA_ARRAY1", "DATA_ARRAY2", "DATA_POINTS"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Removed Other Columns",{{"TEST_DATE", type date}, {"TEST_TIME", type time}}),
     #"Added Custom3" = Table.AddColumn(
   #"Removed Other Columns",
   "ALL",
   each Table.Buffer(Table.AddIndexColumn(
     Table.Combine(
       List.Transform(
         List.Zip(
           {
             List.Buffer(List.FirstN(
               List.Transform(
                 Binary.Split([DATA_ARRAY1], 4),
                 each BinaryFormat.ByteOrder(
                   BinaryFormat.Record([val = BinaryFormat.SignedInteger32]),
                   ByteOrder.LittleEndian
                 )(_)[val]
               ),
               [DATA_POINTS]
             )),
             List.Buffer(List.FirstN(
               List.Transform(
                 Binary.Split([DATA_ARRAY2], 4),
                 each BinaryFormat.ByteOrder(
                   BinaryFormat.Record([val = BinaryFormat.SignedInteger32]),
                   ByteOrder.LittleEndian
                 )(_)[val]
               ),
               [DATA_POINTS]
             ))
           }
         ),
         (x) => Table.FromRows({x}, {"DATA1", "DATA2"})
       )
     ),
     "Secondes",
     1,
     1
   )
 )),
 #"Expanded ALL" = Table.ExpandTableColumn(
   #"Added Custom3",
   "ALL",
   {"DATA1", "DATA2", "Secondes"},
   {"DATA1", "DATA2", "Secondes"}
 ),
    #"Removed Columns" = Table.RemoveColumns(#"Expanded ALL",{"CFG_FILE", "DATA_ARRAY1", "DATA_ARRAY2","DATA_POINTS"})//Here I am removing the binary columns
in
    #"Removed Columns"

Then use Table.Buffer instead.