I've used this for self hosting contacts and calendar for many years now and it had been very low maintenance and good. Shared calendar with SO, synced across all devices. I even copy/paste pics of many contacts to have little icons and stuff in the db. Love it.
Same for me, it was basically set&forget. I recently added the InfCloud integration, which basically is a webclient for caldav/carddav, hosted within the radicale instance, which is very nice if you want to check things without your device.
This is what I've been using, but it appears to be abandoned now?
I finally got the caldav part of it to work for a group of people using various flavors of Mac, Linux, and Windows -- PCs and phones. It was a huge pain in the ass, because each client accepted a different form of base-url-plus-calendar-locator, and some very non-technical users were on the other side of the planet, and it took weeks of trial and error before we got everything working.
Carddav looks hopeless, I can't even something that works between DavX5 on my android phone, and whatever the hell my wife's iPhone needs, and we're in the same room.
The iphone seems to be very particular about which caldav/carddav implementations it works with. I had to move through 2 different email/caldav/cardav providers before landing on mailbox.org, whose implementation sync fine with the iphone ime.
https://radicale.org/2.1.html