Optimizing multiple replacements

Thank you! That helped.

I rewrote code a bit, to replace not with Text.Replace, but with Table.ReplaceValue.

Here is the result (all steps shown):

let
    SourceTable = Excel.CurrentWorkbook(){[Name="SourceData"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(SourceTable,{{"First name", type text}, {"Middle Name", type text}, {"Last Name", type text}, {"personal title", type text}, {"generation", type any}, {"First Name (latin)", type text}, {"Last Name (latin)", type text}, {"Birthday", type date}, {"Hire date", type date}, {"Title", type text}, {"Company", type text}, {"Department", type text}, {"Language preferences", type text}, {"Email", type text}, {"Phone", Int64.Type}, {"Cell phone", Int64.Type}, {"Office location", type text}, {"Office", type any}, {"Manager", type text}, {"Dotted-line manager", type text}, {"Employee Number", Int64.Type}, {"Employee ID", Int64.Type}}),
    #"Capitalized Each Word" = Table.TransformColumns(#"Changed Type",{{"First name", Text.Proper}, {"Middle Name", Text.Proper}, {"Last Name", Text.Proper}, {"personal title", Text.Proper}, {"First Name (latin)", Text.Proper}, {"Last Name (latin)", Text.Proper}, {"Dotted-line manager", Text.Proper}}),
    #"Lowercased Text" = Table.TransformColumns(#"Capitalized Each Word",{{"Email", Text.Lower}}),

    //Get table of word replacements
    Replacements = Excel.CurrentWorkbook(){[Name="Replacements"]}[Content],

    //Get list of strings to replace
    ReplaceWhat = List.Buffer(Replacements[Column1]),

    //Get list of strings to replace with
    ReplaceWith = List.Buffer(Replacements[Column2]),
    
    //A non-recursive function to do the replacements
    ReplaceByList = (Input, Columns)=> 
       //Use List.Generate() to do the replacements
       List.Last(List.Generate(
          ()=> [Counter=0, ProcessedData=Input], 
          each [Counter]<=List.Count(ReplaceWith), 
          each [Counter=[Counter]+1, 
                ProcessedData=Table.ReplaceValue(
                                                 [ProcessedData], 
                                                 ReplaceWhat{[Counter]}, 
                                                 ReplaceWith{[Counter]},
                                                 Replacer.ReplaceText,
                                                 Columns)], 
          each [ProcessedData])),
 
    //Add a calculated column to call the function on every row in the table
    //containing the text to change
    #"Replaced Diacritics" = ReplaceByList(#"Lowercased Text",{"First Name (latin)","Last Name (latin)"})
in
    #"Replaced Diacritics"

Not sure this is the best way, but works reasonably fast on my limited data set.  Don't like the thing with counter and removed explicit subfunction definitions.