As a user, I would like to recommend you use MacSonik OLM to PDF Converter for Mac its GUI Process single as well as multiple OLM Files to PDF and many formats in just few Minuites.
MacSonik OLM to PDF Converter for Mac is a dependable and fast software solution for converting Mac Outlook emails to PDF. The software includes a number of features that allow users to convert OLM to PDF on MacOS.

https://www.macsonik.com/olm/pdf/