IONOS
IONOS also provides CalDAV hosting, even just with their "Mail Basic" plan.
To configure a calendar client (like Fantastical), you just need the CalDAV URL, which can be found here:
Address like https://dav.mailxchange.1and1.co.uk/caldav/xxxxxxxxxxxxxxxxxxxxx.
Added as account to Fantastical:
Fruux
From Germany.
Any device, anywhere
Always updated
Always secure
New device, no hassle
Premium support
Open standards
Serious about privacy
Read some challenges to be expected with Apple devices.
Most importantly, tried to sign up to test but got an error:
Moved on.