Needing some help with how to build this table. Custom Columns.

This something like this what you are looking for?

let
    defaultPID = "25416",
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjQwVNJRCk4tKcnMSwcxI5ViddCEjbALGwOZfpjCJkiqTVHN9sMUNsIubIzdEBO4aiNTE0MzbC5HkzDCpcMYlw6oHbEA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [PID = _t, Name = _t, Enabled = _t]),
    set_types = 
    Table.TransformColumnTypes(
        Source,
        {
            {"PID", Int64.Type}, 
            {"Name", type text}, 
            {"Enabled", type text}
        }
    ),
    defaultTable = 
    Table.SelectRows(Source, each [PID] = defaultPID),
    merge_tables = 
    Table.NestedJoin(
        Source, 
        {"Name"}, 
        defaultTable, 
        {"Name"}, 
        "Source", 
        JoinKind.LeftOuter
    ),
    expand_default_enabled = 
    Table.ExpandTableColumn(
        merge_tables, 
        "Source", 
        {"Enabled"}, 
        {"DefaultEnabled"}
    ),
    sort_table = 
    Table.Buffer(
        Table.Sort(
            expand_default_enabled,
            {
                {"PID", Order.Ascending}, 
                {"Name", Order.Ascending}
            }
        )
    )
in
    sort_table