Find Column Name in String and Replace with Record Field from that Column Name

Hi Kenneth_Sarver ,
you can do that in one step like so:

let
    Source = Table.FromRows(
        Json.Document(
            Binary.Decompress(
                Binary.FromText(
                    "i45W0rNU0FJwVNBW0DMEMpwUdBX0DEBCzko6SgFB/i6hziFAlmuIh6Ofvw+QFeTpF6wUGwsA",
                    BinaryEncoding.Base64
                ),
                Compression.Deflate
            )
        ),
        let
            _t = ((type nullable text) meta [Serialized.Text = true])
        in
            type table [Formula = _t, A = _t, B = _t, C = _t]
    ),
    #"Changed Type" = Table.TransformColumnTypes(
        Source,
        {{"Formula", type text}, {"A", type text}, {"B", type text}, {"C", type text}}
    ),
    StitchTogether = Table.AddColumn(
        #"Changed Type",
        "Result",
        each Text.Combine(
            List.ReplaceMatchingItems(
                Text.Split([Formula], " "),
                List.Skip(Table.ToRows(Record.ToTable(_)))
            ),
            ""
        )
    )
in
    StitchTogether

 General method for this is described here: Multiple replacements or translations in Power BI and Power Query – The BIccountant
If you want to follow allong and understand what's going on in the formula, please paste this code into the advanced editor and follow the steps:

let
    Source = Table.FromRows(
        Json.Document(
            Binary.Decompress(
                Binary.FromText(
                    "i45W0rNU0FJwVNBW0DMEMpwUdBX0DEBCzko6SgFB/i6hziFAlmuIh6Ofvw+QFeTpF6wUGwsA", 
                    BinaryEncoding.Base64
                ), 
                Compression.Deflate
            )
        ), 
        let
            _t = ((type nullable text) meta [Serialized.Text = true])
        in
            type table [Formula = _t, A = _t, B = _t, C = _t]
    ), 
    #"Changed Type" = Table.TransformColumnTypes(
        Source, 
        {{"Formula", type text}, {"A", type text}, {"B", type text}, {"C", type text}}
    ), 
    ReplacementsList = Table.AddColumn(
        #"Changed Type", 
        "RelevantColumns", 
        each List.Skip(Table.ToRows(Record.ToTable(_)))
    ), 
    FormulaToList = Table.AddColumn(
        ReplacementsList, 
        "SplitFormulaToList", 
        each Text.Split([Formula], " ")
    ), 
    Replacement = Table.AddColumn(
        FormulaToList, 
        "Replacement", 
        each List.ReplaceMatchingItems([SplitFormulaToList], [RelevantColumns])
    ), 
    StitchTogether = Table.AddColumn(Replacement, "Result", each Text.Combine([Replacement], ""))
in
    StitchTogether