

I’ve been using Ubuntu server on my server for close to a decade now and it has been just rock solid.
I know Ubuntu gets (deserved) hate for things like snaps shenanigans, but the LTS is pretty great. Not having to worry about a full OS upgrade for up to 10 years (5 years standard, 10 years if you go Ubuntu pro (which is free for personal use)) is great.
A couple times I’ve considered switching my server to another distro, but honestly, I love how little I worry about the state of my server os.
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