I've recently (in the last week) added my contacts and manage my calendar via nextcloud locally. Davx synchs to my android devices, nextcloud is synched to my haos VM to help me remember bin nights / other appointments. For someone with ASD + ADHD it's a godsend.
I currently have Nextcloud and am looking to move away from it.
Mainly because my calendar-subscriptions somehow broke and all calendars i subscribe to now are just empty (the old ones are still populated),
but also because it makes the subscribed-to calendars available as WebCal, which Thunderbird doesn't recognize.