The supposed case sensitive problem

Try this example code in Power Query. It converts your text values into separate unicode characters, so will be unique between your different text case examples:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45W0it3DnZRitUBssKT4SznYjgrOAXCKk8uToGLAWVjAQ==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [AGILLIC_ID = _t]),
    addAgillic_Char = Table.AddColumn(Source, "AGILLIC_CHAR", each List.Transform(Text.ToList([AGILLIC_ID]), each Character.ToNumber(_))),
    extractAgillic_Char = Table.TransformColumns(addAgillic_Char, {"AGILLIC_CHAR", each Text.Combine(List.Transform(_, Text.From), "-"), type text})
in
    extractAgillic_Char

Output:

Pete

Thank you. I ended up using a concat of that ID and Email since even that smart solution You gave, did give non-uniques. But thanks again for trying 🙂