If the server hoster supports it (Hetzner apparently does), you can enable KVM and install a previously prepared image.
If the server hoster & hardware supports it, you can login remotely to the server management interface (like HP iLO) and install an image this way.
If you don't have above options or simply don't want to do it this way, you can also bootstrap via SSH. But instead of manually typing in shell commands, you will automate it in some way with custom scripts and/or tools like Ansible.
If you don't have above options or simply don't want to do it this way, you can also bootstrap via SSH. But instead of manually typing in shell commands, you will automate it in some way with custom scripts and/or tools like Ansible.