convert olm to csv

Just what was archived to the the olm file?

It can include many items including mail messages

This

https://support.office.com/en-us/article/Export-or-manually-archive-Outlook-item s-281a62bf-cc42-46b1-9ad5-6bda80ca3106

includes archiving/exporting contacts to tab-delimited text file

Export from what? Apple's Addressbook/Contact app or something else?

If I remember correctly Outlook supports standard VCard files but with an important limitation, it cannot process a multi-card VCard file i.e. each contact needs to be in an individual file. I mention this because if you are wanting to move contacts from Apple's Addressbook then it can export as VCard format but cannot export as OLM format. You can force Apple's app to export as individual VCard files by holding down the Option key when dragging the contacts to a Finder folder.

See Contacts: Export and import your contacts