johnrboren
I had a similar issue back in 2020.  
Error:  The font: Segoe UI Emoji does not support the necessary glyphs.
Was there ever a fix for this?  I have another RTF that has embedded emojis from people's phone text messages, and it looks like all symbols when saved in PDF format.
This occurs when TppReport.PDFSettings.EmbedFontOptions.efAllFonts:=true
Works fine if I print to a printer, but not PDF using:
  ListRpt.DeviceType:=dtPDF;
02CC19FE|ppPDFUtils.pas    |ppPDFUtils    |TppPDFUtils      |GetGlyphIDs
02C93D15|ppPDFToUnicode.pas|ppPDFToUnicode|TppPDFToUnicode  |ProcessCMapStream
02C9403C|ppPDFToUnicode.pas|ppPDFToUnicode|TppPDFToUnicode  |ProcessCMapStream
02C94372|ppPDFToUnicode.pas|ppPDFToUnicode|TppPDFToUnicode  |WriteToUnicodeCMap
02C94266|ppPDFToUnicode.pas|ppPDFToUnicode|TppPDFToUnicode  |SaveToUnicode
02CA02EC|ppPDFFont.pas     |ppPDFFont     |TppPDFFont       |SaveFont 
02D2F0E4|ppPDFDevice.pas   |ppPDFDevice   |TppPDFDevice     |EndJob