How do I fix error "gs" ignored when using ghostcript for reducing pdf file size?

Question

I am trying to reduce the filesize of a pdf using ghostscript. I found the command here: https://tex.stackexchange.com/questions/18987/how-to-make-the-pdfs-produced-by-pdflatex-smaller

gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.5 -dNOPAUSE -dQUIET -dBATCH -dPrinted=false -sOutputFile=foo-compressed.pdf input_file_name.pdf
   **** Error 'gs' ignored -- ExtGState missing from Resources.
        Output may be incorrect.

I also executed the command without -dQUIIET and -dNOPAUSE, but that didn't clarify the problem:

GPL Ghostscript 9.55.0 (2021-09-27)
Copyright (C) 2021 Artifex Software, Inc.  All rights reserved.
This software is supplied under the GNU AGPLv3 and comes with NO WARRANTY:
see the file COPYING for details.
Processing pages 1 through 72.
Page 1
   **** Error 'gs' ignored -- ExtGState missing from Resources.
        Output may be incorrect.
>>showpage, press <return> to continue<<

I don't know what ExtGState means hence that I don't know what further steps are needed to solve the problem.

EDIT1

The command does put a PDF file out that is smaller. So it seems to work. I am simply unsure what the error means and whether it needs to be fixed and how.

adding -dPDFSETTINGS=/prepress does not remove the error.

Pdffonts

pdffonts original.pdf
name                                 type              encoding         emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
RLEATT+Aniron-Bold                   CID TrueType      Identity-H       yes yes yes     11  0
JETQLW+CrimsonPro-Regular            CID TrueType      Identity-H       yes yes yes     13  0
CZPFND+CormorantSC-Bold-Identity-H   CID Type 0C       Identity-H       yes yes yes     19  0
APXFPL+CrimsonPro-Italic             CID TrueType      Identity-H       yes yes yes     74  0
VTLLQQ+CrimsonPro-Bold               CID TrueType      Identity-H       yes yes yes    148  0
BCDEEE+Calibri                       TrueType          WinAnsi          yes yes no     770  0
BCDFEE+MS-PGothic                    TrueType          WinAnsi          yes yes no     774  0
BCDGEE+Wingdings-Regular             CID TrueType      Identity-H       yes yes yes    778  0
BCDHEE+Calibri-Bold                  TrueType          WinAnsi          yes yes no    2816  0
CXSUEN+LMMono10-Regular-Identity-H   CID Type 0C       Identity-H       yes yes yes   2888  0
BCDEEE+MinionPro-Regular             TrueType          WinAnsi          yes yes no    2899  0
BCDFEE+Aniron-Bold                   TrueType          WinAnsi          yes yes no    2904  0
BCDGEE+TimesNewRomanPS-BoldMT        TrueType          WinAnsi          yes yes no    2909  0
BCDHEE+MinionPro-Bold                TrueType          WinAnsi          yes yes no    2915  0
BCDIEE+MinionPro-Regular             CID TrueType      Identity-H       yes yes yes   2922  0
BCDJEE+TimesNewRomanPSMT             TrueType          WinAnsi          yes yes no    2929  0
BCDKEE+SymbolMT                      CID TrueType      Identity-H       yes yes yes   2937  0
BCDLEE+ArialMT                       TrueType          WinAnsi          yes yes no    2946  0
BCDMEE+Aniron                        TrueType          WinAnsi          yes yes no    2955  0
BCDNEE+MinionPro-Bold                CID TrueType      Identity-H       yes yes yes   2968  0
BCDOEE+MinionPro-BoldIt              TrueType          WinAnsi          yes yes no    2978  0
BCDPEE+MinionPro-It                  TrueType          WinAnsi          yes yes no    2983  0
BCEAEE+TimesNewRomanPS-ItalicMT      TrueType          WinAnsi          yes yes no    3051  0
AJWSEY+CrimsonPro-BoldItalic         CID TrueType      Identity-H       yes yes yes   3195  0