Dear Employer,
I have read your project description; However, I would like to get more info about the problem that you are facing because LibreOffice Calc has an export as pdf option and it works well.
Best regards
P.S.: Check if you have the latest version of LibreOffice, as it doesn't update automatically. You need to go to their website, download the latest version, uninstall your current version and install the downloaded one. Good luck