There are two solutions you can try here: first is a manual trick and second one is a professional tool. First you should try the manual trick before purchasing any 3rd party paid software. Though the manual trick doesn't convert OLM to PST format, but it can help you transfer emails and other mailbox data from Outlook for Mac to Windows Outlook. You can refer to this blog post complete information - Convert OLM to PST Manually – An Easy Step-by-Step Guide | N. Sem's Blog
If the manual trick shared in the above blog post fails or doesn't work, then you only you should use a professioanl converter tool. Download free demo version of OLM to PST Converter software to convert OLM files into PST format without causing any changes or alteration to the origianl mailbox. I hope it would be helpful here.
Thanks and best regards.