Absolutely. There are different options.

If you want something simple, just contacts and calendar, check out Radicale. I’ve been running radicals for years and its great.

If you want something more like a whole google suite replacement (contacts, calendar, drive, docs, photos, etc), look at Nextcloud

Yup, that would be CardDAV and CalDAV respectively. There’s a number of programs that does this. Ones I remember are Nextcloud, Radicale and Baikal.

I found Baikal the easiest to setup :) never had to touch it again and works on all my platforms. Many caldav servers have issues with iOS because the devs are bad at caldav.

NC works but it’s bloated if that’s all you want