There are a number of tools available for migrating OLM files to PST file format. But, here is another software vMail OLM to PST Converter software, that I would like to recommend that will help you with an easy and quick conversion of OLM files to PST format including all emails, contacts, calendars, and other items.
Know more info- https://www.vsoftware.org/olm-to-pst-converter.html