How do you reduce a .pdf file in Preview without loosing quality, MBP Catalina 10.15.4

Hello, I have a 29M pdf file that I want to reduce so I can mail it. I tried the Quartz feature in Preview but the file quality was terrible. I also went to ColorSync utility and reduced it there, but that was just as bad.

Is there any way to get reduced size pdf that is good quality? Any good softwares?

Thank you!!