Hope you are doing well and sorry to hear that.
Is this issue occurring only in SharePoint or otherwise as well? Please try to create the PDF using Acrobat Pro on your computer locally and check.
What is the workflow you are doing to create the PDF file? please share a small video recording of the steps you are doing for a better understanding.
A font can be embedded only if it contains a setting by the font vendor that permits it to be embedded. For more information, please check the help page https://helpx.adobe.com/acrobat/using/pdf-fonts.html