I just discovered something suuuper cool! If you have a domain on https://www.gandi.net it comes with a #cardDAV server already set up for free linked to your domain! Why is that cool? Well if you dont want google or apple to know who is in your address book on your phone you can set up an alternative host for it. I just got it set up on this Mac I am using for some work stuff after finding this page https://docs.gandi.net/en/gandimail/sogo_webmail/caldav.html