If you want sync to your phone, just set up a VPN. Now your phone and mobile computer can always access your services. I use SoGO, it has calendar hosting, authenticated sync which you can use with davx on android and the web interface is basic but usable. You can also enable mail, tasks and contact sync all in one.
Used to be names from Neuromancer like “ono-sendai” and variations of that.
Now laptop is “flat”, server is named after it’s purpose like log, mail, mon, hosting, storage, etc.