High memory consumption during file saving

Could you elaborate why these two flags are important for you?

SDFDoc.SaveOptions.e_compatibility is only if you need to generate a PDF1.4 spec, which is exceedingly rare now.

SDFDoc.SaveOptions.e_hex_strings I have never seen anyone actually use this option, let alone need it.

Normally the only flag you use is e_linearized to generate a Fast Web View PDF file.

How does using the e_linearized flag only work for you?