or... maybe this effort;

Sub RemoveCharacterStylesFromFootnotesExceptSuperscriptInFootnoteReferences()
    Dim footnoteRange As Range
    Dim charStyle As Style
    Dim charRange As Range
    Dim supRange As Range
    Dim supStyle As Style
    ' Set the style for superscript within footnote references
    On Error Resume Next 
    ' Handle potential error if style doesn't exist
    Set supStyle = ActiveDocument.Styles("Footnote Reference")
    On Error GoTo 0
    If supStyle Is Nothing Then
        MsgBox "Footnote Reference style not found. Macro will remove all character styles from footnotes.", vbExclamation
    End If
    ' Loop through all footnotes
    For Each footnoteRange In ActiveDocument.Footnotes
        ' Loop through all character styles in the footnote
        For Each charStyle In ActiveDocument.Styles
            If charStyle.Type = wdStyleTypeCharacter Then
                ' Loop through all ranges with the current character style
                Set charRange = footnoteRange.Range.Duplicate
                With charRange.Find
                    .ClearFormatting
                    .Style = charStyle
                    .Forward = True
                    .Wrap = wdFindStop
                    .Format = True
                    .Execute
                    Do While .Found
                        ' Exclude superscript within footnote references
                        If Not (Not supStyle Is Nothing And charStyle.NameLocal = "Superscript" And charRange.InRange(supStyle.Range)) Then
                            ' Remove the character style
                            charRange.CharacterStyle = ""
                        End If
                        ' Find the next occurrence
                        .Execute
                    Loop
                End With
            End If
        Next charStyle
    Next footnoteRange
End Sub