In 2009 I wrote about how it was getting harder to move contact information out of Outlook into something else (like macOS Contacts). I wrote about some options, but that's not what I do now.
Here's what I do (tested in Mojave, which I'm still using because Aperture):
- Create a simple list Contacts view. I usually only want people so I sort by last name. In a few cases last name of people is blank so I fix that.
- Now create an empty email. Drag Contacts from Outlook's view into the email body. It has to be to the email, dragging to desktop creates a .msg file. It might fail if you do too many so I distribute 300-400 contacts across 4 separate emails. Outlook creates a vCard file as an attachment. It resolves the email too, so instead of an Outlook x400 (?) you get a proper email address.
- Send the email to your Mac
- On the Mac download all attachments. They show as VCF files and macOS renders them quite well. If they have photos the photos show within the card icon. Spotlight indexes them all. You don't even need to bother with dropping them into Contacts (though that's easy to do, you can drop them into your Contacts Groups (folders)).