If you're at least a bit into home-lab tinkering, you could run NextCloud from a Docker container on your NAS or home server or RPi. For external access limited to your family's devices, you could use Tailscale.
But yes, you could just have Hetzner host it for you for a handful of Euros a month.
But yes, you could just have Hetzner host it for you for a handful of Euros a month.